Tuesday, November 30, 2021

November 31st Overnight Audio, Marsh Shoreline, SMNWR


Into the Saw Palmetto dominated pine flatwoods to the marsh waterline where I'll set up recorders for overnight audio collection

An hour of sunlight left, heading into the wet saw palmetto dominated pine and cypress lined sloughs to set up Sony recorders for overnight field recordings. Lots of migratory birds have made their way to the St. Marks National Wildlife Refuge and they are quite vocal after dark & just before sunrise. I enclose the recorders set at 24 bit/96000 (50% gain) in drybags and cover the stereo mics (PIP power lav type, usually MikroUsi or Clippy) with fuzzy wind covers. Hang the drybags on a tree branch, draping mics over branches or using a wire hair tie place around trunk with a binaural mic arrangement. So excited to go back out at sunrise & collect recorders. Not quite like sleeping under the stars but listening to the night sounds of the marsh & flatwoods is healing. Check out bio link for a sampling of field recordings from the marshes of SMNWR 

Wednesday, November 24, 2021

Organic Hemp Cultivation, Integrated Pest Management (IPM) & Birds

 We encourage birds to make themselves home here in the Arendell Hill nursery gardens.

Wild birds, song birds, raptors and more.  Winged creatures serve an important part of our Organic IPM

I consider birds to be better than 'human help' at picking caterpillars and other potential pest insects out of our gardens.  Songbirds can keep the ground and shrubbery around a hemp cultivation area significantly free of larvae that are crawling around looking for leaves or flower buds to chew on.  Larger birds also, like red shouldered hawks here are vigilant in keeping the nursery free of disease vectoring rodent populations. 

Winged creatures have a definite advantage over crawling pests.  Winged predators can conduct reconnaissance across a ground area much quicker than most crawly pests can escape.  It is true that many insects can fly and are beneficial in their own ways, such as for pollination.  The advantage however lies with birds though due to their size, advanced development of senses and ability to quickly forage across large areas of garden.

Maintaining quality bird habitat for hemp farms should include practices that ensure ample bird forage provisions exist.  Feeders are one obvious way to attract birds and work well in creating a basic Integrated Pest Management program.  Yet bird feeders are just a start.  Native landscape plants that flower, fruit and produce seed are another worthwhile addition to bird feeders in hemp cultivation areas.

Importantly, once the grower begins to attract birds to their hemp growing area and the birds begin their caterpillar and pest insect control duty, the grower must also ensure that the farm provides a place for the birds to 'stay' and nest.  Communal habitat is best established by planting native landscape and wildlife value shrubs.  

American holly, Ilex opaca, provides forage and evergreen communal habitat to wild songbirds and as such can be an important part of an Organic Hemp IPM program. 

Native shrubs, rather than horticultural imported shrubs, will always be a wild songbird's and raptor's preference, for the native shrub's habit and familiarity are transcribed by countless previous generations into a bird's DNA.  Simply put, the wild songbirds are attracted to those native shrubs they and their ancestors have always lived in and around.   

It is true that some non-native horticultural shrubs and plants will also be utilized by wild birds.   However the net benefit to the hemp farm efficiency matrix will be reduced when using non-native landscape species.  In fact, it is possible non-native landscape plants can cause significant ecological systems damage.  When the growing ecosystem matrix becomes unbalanced pest pressure will increase.

As we will see in other posts, not only do native plant species support all important bird populations across the hemp farm, but native plant species also provide a number of other important pest control and nursery management functions.

We will also discuss in future posts, how to visualize the hemp farm bio-geophysical ecosystem matrix.  Though the name 'bio-geophysical ecosystem matrix' may sound complex, the concept is a simple one.  Everything affecting the hemp farm makes up the matrix.  There are many variables, such as birds, wildlife, rain, wind, temperatures, pests, soil, water and others.  The way these variables act upon and influence hemp plant growth in the garden is what the matrix is all about.

Another term I like to use when thinking about the ecosystem matrix is the phrase 'Languages of Nature'.  Each variable asserts an influence, good or bad, on the hemp plants.  Each good or bad influence can be known through interaction with our senses.  Ecosystems communicate the effects of most impacts they experience through measurable responses. An expert hemp farmer 'reads' and understands these ecosystem responses and utilizes the information to maximize crop efficiencies.

Importantly, songbirds and raptors are not the only winged creatures employed by organic hemp and plant nursery growers as part of an organic IPM program.  Chickens, bats and other critters have been successfully integrated into hemp farm pest control programs.  We will discuss these too in future posts.

Finally, it must be understood that birds can be vectors of plant diseases.  However when weighing the risks of potential bird vectored plant diseases versus the insect control benefit, the pest control benefit is usually greater than the disease risk.  

IPM risk benefit analysis can be established through trial and error on the farm, through research of peer reviewed literature and also through coordination with experts working with a local agricultural extension service.

Birds are just one part of a hemp farm ecosystem matrix complex, yet they are a beneficial part.  

Now it is time for me to go add bird food to the feeders!



Saturday, November 20, 2021

Organic Hemp Pest Control (IPM) Prescribed and Simulated Burning Importance

 Last post we discussed how Eastern Tent Caterpillars, Malacosoma spp., lay their eggs on the branches, twigs and leaves of hardwood trees.  Once deciduous leaves fall and autumn winds blow twigs to the ground, caterpillar eggs can overwinter in accumulated biomass, groundcover vegetation and the dirt.

Insect, probably caterpillar larve hatched and beginning to weave silken web for protection

Until humans began the suppression of seasonal lightning fires, heat generated by combustion of dry biomass served to control population numbers of many pest organisms including caterpillars.

Natural seasonal fires served to cap population numbers of many pest insects.

Many farming operations today have reintroduced the practice of land fire management with prescribed burning.  Prescribed burning involves the intentional application of fire to plots for the purpose of weed and invasive plant control, pest management, biomass fuel reduction (safety), hunting plantation management and many other purposes.

Often times though, prescribed fire may not be practical for safety sake and sometimes burning is simply impossible, say in a greenhouse for example.  In the event a hemp cultivation area is located in an area where burning is not practical then leaf litter and grounds cleaning becomes a pest management tool of utmost importance.

Pest organisms take advantage of many transportation mechanisms referred to as vectors, to increase, sustain and spread their population numbers.

Leaves and twigs are subject to seasonal winds.  Once deciduous leaves fall from a branch they may be blown hundreds of feet from the tree from which they grew.  Over time these leaves can be carried significant distances via strong breezes.  

Moth laid caterpillar eggs attached to wind blown leaves and twigs can stay viable through winter months and hatch when appropriate weather conditions develop during spring months, increasing hemp pest population numbers.

Leaf litter management will not cause moths or caterpillars to go extinct.  On the contrary, managing tree leaf and twig drop can benefit the moth and caterpillar populations.  Excess caterpillar population numbers and overgrowth may lead to weakened individuals, spread diseases and lead to larval food shortages.  Good leaf management mimics nature's own way of managing insect populations.

As mentioned above, wildfires and lightning fires historically served as a limiting control on caterpillars and other insect egg spread.  As fire frequency diminished, pest pressure increased.  It is not really a big surprise that as the natural complexities of ecology change, a result of human actions, caterpillar and pest overpopulation occurrences are becoming more commonplace.

Today, because of the lack of seasonal wildfires it is important to 'simulate' fire's pest destruction effects by mechanically removing leaves that fall across the hemp cultivation areas.  Importantly, the grower should not only remove tree, leaf and twig litter from active cultivation areas but also from adjacent areas of the cultivation plot or greenhouse area.  Caterpillars and other leaf borne pests can crawl long distances.

Backpack blowers, rakes, lawn mower debris collection bags and other equipment can be employed to collect tree drop biomass (litter).

Once the twigs and leaves are gathered it is necessary to burn, compost or mechanically degrade the biomass to actually destroy pest eggs.  A big pile of leaves in the corner of the property can serve as a giant pest incubator.

Today, understanding and managing the leaf-twig-wind vector complex is just one of many important factors comprising an organic hemp growing ecosystem.

Seasonal fire is always helpful, but not always practical.  Therefore an organic hemp growing IPM program is benefited from simulated fire practices.

Predictable management of pest occurrences is a goal of organic pest IPM.  Keeping leaf litter under control can help keep hemp crops pesticide and toxicity free, and avoid diseases, leaf destruction or bud feces damage.

Wednesday, November 17, 2021

Eastern Tent Caterpillars (Malacosoma spp.) and Other Caterpillars in Hemp Cultivation

 Quality, organically grown hemp can bring a high level of demand and offer significant economic gain to the organic grower.  But tent caterpillars can devastate any crop, especially plump, fresh leaves and buds in a matter of hours when they are in a feeding frenzy.  In the eastern U.S. there are several species of tent caterpillars including the Forest Tent Caterpillar, Malacosoma disstria and the Eastern Tent Caterpillar, Malacosoma americanum.  

Eastern Tent Caterpillars crawling across the pavement in search of host plant material

The forest tent caterpillar typically weaves silken mats on tree trunks where they congregate after feeding and for protection.  Similarly, silky tents observed in the branches of trees are usually constructed by the eastern tent caterpillar.

Does Malacosoma americanum pose a serious threat to hemp?  Hemp may not be the first host plant of choice for the eastern tent caterpillar but there are reports in literature (Alexander 1984b) of M. americanum exerting negative pest influence on hemp.  It is possible that once a hungry population of tent caterpillars encounters hemp in cultivation, the caterpillars devour much of a crop without a second thought.  Moreover, in addition to the defoliation, many caterpillars leave copious amounts of feces in hemp's flower buds.

Regardless, this past year brought significant numbers of tent caterpillars to Arendell Hill's trees.  Several of our mature fruit trees were attacked by the caterpillars.  Unfortunately, they ate the majority of buds, blossoms and leaves from many of our citrus and fruit trees. 


It is easy to see just how many tent caterpillars are in a population once they are in their 'tent'.   During their developmental phases, tent caterpillars will crawl out of their nest and feed on the host plant leaves.

Caterpillar eggs can survive the winter attached to leaf litter and fallen tent masses

Worth repeating because of the tremendous potential economic damage a hemp cultivator can suffer is the fact that in addition to tent caterpillars damaging hemp plants by eating their foliage, caterpillars can leave copious amounts of feces as they crawl across and into, eating hemp flower buds.  A feces filled flower bud will usually be considered a total loss.

Eastern Tent Caterpillar's woven 'tent'.

The hemp farmer can avoid significant tent caterpillar damage by taking a few common sense pest management steps including; good housekeeping and a focus on cleanliness, support of biodiversity,  understanding host plant potential and actual pest identification.

First it is important to be able to correctly identify any potential hemp pest caterpillar.  Here in Florida the University of Florida's (UF) agricultural extension program can offer important help to farmers when it comes to growing almost any crop, including hemp.

Most counties in the state have an agricultural agent assigned and if the agent does not personally have the particular pest control experience one needs they will have access to the experts who do.

Here is the link to 'Find Your Local Agricultural Extension Office' website.

Your local agricultural extension agent will be able to assist you in identifying which of the species of tent caterpillars your growing operation may be challenged with.  In addition to the tent caterpillar issue, your UF extension agent can help with most any other crop pest issues. 

Along with the agricultural extension services discussed above, the internet is another resource to assist with in pest caterpillar identification.  One hack I always turn to includes snapping a photo with my phone camera and in turn doing a Google image search.  Although not as accurate by any means as the extension expert's identification help, the Google image search usually narrows down pest species choices to family or genus.  Many times however, I've been able to successfully identify caterpillar types through the Google image search function.

Once the caterpillar has been identified, in this case we've identified some of our caterpillars as the Eastern Tent Moth Caterpillar rather than the Forest Tent Caterpillar, then the grower must decide what level of attention needs to be aimed at the potential pest caterpillar.

If the ecological, environmental and economic damage potential is great then the hemp farmer may want to consider an eradication or extra strong management approach.  Eradication often involves pesticide applications, that though they may be considered 'organic' still possess moderate toxicity and lower the value and quality of the final hemp crop.  Additionally, organic pesticides ultimately make a pest problem worse by unbalancing of the farm's long-term, functioning ecosystem dynamics.

If the ecological, environmental and economic damage potential is more moderate but certainly in need of addressing then a focused management approach may be advised.  Moderately focused approaches can be taken many times when pest caterpillars first begin to appear and can include; traps, hand removal, facility cleaning, personal protective equipment, soil and container sterilization and more.

Caterpillar eggs may be attached to fallen leaves and hatch the next warm season.

Finally, if the potential pest is a slow reproducing and easy to control organism them monitoring may be all that is necessary.  Always keep good notes, including dates, times, events, pest numbers and types and control measures taken. 

One of the most common vectors of caterpillar and larvae are fallen leaves

Once the caterpillar has been identified and the level of necessity for adequate response has been decided them control actions can be implemented.

Most importantly, it is crucial to understand the best ecological, environmental and economic outcome will be achieved only when the hemp farmer can bring the growing operation into balance with the surrounding ecosystem that itself is functioning within normal ecological variables.  What this means from a pest control perspective is that any hemp operation will be mostly affected by pests which are themselves existing in an unbalanced state in the soil, vegetation and air in and around the hemp farm.

An eradication effort on the hemp growing area will be effective only as residual pesticide exists.  As soon as the pesticide is degraded additional pests will enter the growing area from the surrounding ecosystem where they are out of balance with respect to excess population numbers.  As the caterpillars continue to overwhelm more pesticides must be applied.  Eradication and pesticide measures use can easily turn into an unnecessary and damaging repetitive cycle.

In the end, many times eradication efforts do more crop damage than the original pest issue the grower sought to control.

However, once the surrounding ecosystem is balanced with respects to ecological dynamics then hemp crop pest control becomes much more manageable.

The hemp farmer must also consider and strive for ecological balance within the totality of their plot, not just their greenhouse or outdoor hemp garden.

As a hemp farmer I can keep tent caterpillars out of my green house on a consistent basis only if the surrounding land is balanced with normal tent caterpillar population dynamics.  If the tent caterpillar populations surrounding the hemp greenhouse are out of balance then eradicating them from the green house will only have momentary benefit.  They will crawl right back in once the pesticide level is no longer a deterrent. 

Supporting a natural ecological balance in and around the greenhouse or growing plot the farmer should manage the growing areas in a native and natural manner.  Area native ecosystems have evolved over the millennia into a harmonious complex system of interacting life forms.

Usually nature has fine tuned native ecosystems to function in a precise balance, one where all forms of life play a part and one where all natural geophysical and climatic conditions help maintain homeostasis.

Once humans become involved though we have a tendency to change an ecosystem's natural variables to suite our plans.  Examples of these impacts include; lack of fire, artificial irrigation, replacement of native plant flora with pest prone landscape plants, alteration of natural hydrology, alteration of native soils, change of noise levels, urban heat island effect and much more.

With respect to our tent caterpillars, annual wildfires suppressed for the safety of lives and property, allow a much greater quantity of tent caterpillar eggs to survive in the ground, on bark and on fallen leaves.

Historically, fallen leaves were usually part of the fuel annual lightening fires burned with and much of the egg bank was burned away.  However with a lack of fire today potential pest eggs can exponentially accumulate, creating population numbers that are much higher than in fire acclimated ecosystems.

In the hemp greenhouse and across the hemp cultivation area it is important to keep leaf litter cleaned up.  Leaves left to lie over the winter, especially those in piles under shrubs or around the base of fences make good incubation areas for next years caterpillars.

In the absence of fire, mowing and raking can help control pest eggs.

Leaf litter control is just one of the many integrated pest management control approaches a hemp grower can take.

I try and visualize my growing area as it would have functioned from a biophysical perspective as it might have before humans arrived.

Of the three pest management approaches mentioned above, an IPM approach to hemp cultivation, based on ecosystem principles consistent with balanced, native communities works best for growing quality, organic hemp products. 

We will look at the value of using native plants and avoiding horticultural landscape plantings around the hemp farm, as well wildlife and other IPM tools in upcoming posts.

Monday, November 15, 2021

Coyote Pack Calls, 1 a.m. St. Marks National Wildlife Refuge

Coyote Pack Calls, Port Leon Road, SMNWR November 2021 1 a.m.

Coyote Pack reconciliation calls after a midnight hunt in the St. Marks National Wildlife Refuge. Recorder placed in a mixed hardwood slough in the midst of a wet pine flatwoods. Sony PCM with stereo microphones in dry bags. Waxing moon, light rain. November 2021. The acoustics of the flatwoods are complex. An abundance of water surface creates wave reflection and 'echos' as well as does the fire influenced open midstory under the acres and acres of pines. Note: Coyote calls are usually a signal for the pack to regather or to call juveniles after nighttime excursions and not necessarily to signal a kill. 

Sunday, November 14, 2021

Night Sounds of SMNWR's HQ Pond.

 Here is an hour long audio of freshwater pond night sounds in the St. Marks National Wildlife Refuge. Audio clip contains Anhinga (their calls are ethereal), Great Blue Heron and Common Gallinule and Catbird, calls post sunset calls from the Headquarters Pond area of the St. Marks National Wildlife Refuge on November 12, 2021. Sony PCM recorder with Clippy272 stereo microphones in a double dry bag placed in the fronds of a Sabal palmetto tree approximately 3 meters from the shoreline. Waxing moon, moderate temperatures and scattered light rain.

Friday, November 12, 2021

Salt Tolerant Native Plants, Turkey Tangled Frog Fruit, Phyla nodiflora

 Old buildings teach me so much about the wind, sun and salt tolerances of native plants.

Phyla nodiflora, Turkey Tangled Frog Fruit growing out of the old brick walls of Fort Pickens, Pensacola Beach

Turkey Tangled Frog Fruit (TTFF), aka Lippia nodiflora (Verbenaceae) has long been one of my favorite Florida native plant species.  First of all I'm enchanted by its name.  Rumor has it that once upon a time a flock of turkeys got their long legs and feet all tangled up in the Frog Fruit vine-like flexible stems. Supposedly all the turkeys then fell over, practically squishing all the happy frogs who were eating the plant's fruit-like flower buds.  Of course this ruckus caused quite a stir with all the butterflies feeding on TTFF's nectar and they proceed to flit about telling the mockingbirds what was happening.  Well you know, once a mockingbird hears a good stanza, it'll be repeated everywhere. To this day the low growing groundcover as been known as Turkey Tangled Frog Fruit.

From time to time, I've been asked for a list of native plants that may be salt, wind and blazing sunlight tolerant.

There are many reference books that discuss optimal growing conditions for native species, but I always find that the best way to learn which native plants do best in any location is to walk around and look at what plants are growing on older buildings in the specific location you are interested in.

Here is a photo of a marvelously healthy Turkey Tangled Frog Fruit growing out of the brick walls of Fort Pickens in Pensacola Beach.

The only irrigation this plant receives is dew, air humidity, ocean salt spray and rain.  The Gulf of Mexico is only a few steps to the south and the just as salty Pensacola harbor is a few steps to the north.

There is no tree canopy around for shade, just hot, glaring sunlight.

The four or five meter per second persistent ocean winds are salt laden and dessicating.

The old brick walls of this fort are a hard place for any plant to survive.  Yet this TTFF specimen is thriving.

Spending time in the field is the very best way to learn what, where and how native plants need to grow.

Thursday, November 11, 2021

Hemp Organic Integrated Pest Management (IPM); Thistles, Painted Lady Butterflies and Larvae

 Almost nothing can do as much damage to hemp plants and flower buds as caterpillars can. 

Painted Lady butterflies are attracted to aster-like wildflowers for use as host plants.

Most larvae go through a number of developmental changes (instars) during their transition from egg into butterfly form.  While in the caterpillar stages these larvae consume as much plant matter as they can and store the foraged protein for future use in egg production as mature butterflies.

There are quite a few caterpillars attracted to and often found on hemp plants.  Today I'd like to briefly talk about the Painted Lady Butterfly, Vanessa spp, butterflies and caterpillars.

Painted Lady caterpillars are often found growing and foraging in hemp leaves and hemp flower buds.  

Painted Lady butterflies will typically lay a single egg on a hemp leaf.  Once the egg hatches and the larvae begins to develop, a thread-like silky mesh will appear wrapped around two or more leaves as the caterpillar builds protective shelter.

Circular chew marks may appear of the edges of leaves as the larvae begin to feed.  In their early stages, the Painted Lady larvae may be light brown colored and spiny.  

During outbreak periods, a large number of Painted Lady caterpillars can significantly damage hemp plants with their voracious plant matter diets.  Not only can the Painted Lady caterpillars eat hemp plant biomass, but they can also (as with any other caterpillar and larvae) leave significant amounts of feces in hemp plant flower buds.  Hemp plant flower buds destined for edible product consumption may be seriously damaged or may even become a total loss.

Painted Lady butterflies and caterpillars serve an important role in our ecosystems however.  Even though they may be considered a pest to hemp cultivation efforts, Painted Lady butterflies should be accepted as a vital component of the ecosystem surrounding hemp cultivation operations.

The key to controlling Painted Lady crop damage lies not in eradication, but in supporting a balanced matrix of insect role within the overall surrounding ecosystem.  Painted Lady butterflies as well as other species are important pollinators for native plants.  Their long proboscis can be more effective at pollination for certain native wildflowers than bees for example.  Native plants are likewise essential for maintaining homeostasis with natural population balances, keeping fungi, bacteria and insects numbers relative to proper balances.

As Painted Lady larvae mature they may develop yellow and black stripes.  One important facet of organic based Integrated Pest Management is an understanding of where pests come from, or pest vector recognition.  Although native insect eradication is not a good idea, and actually a practice that may further aggravate invasive pest problems, it is important to understand where and under what conditions insects thrive.

Painted Lady butterfly host plants include thistles, wild asters and plants in the Boraginaceae and Malvaceae (okra, cotton and mallow) families. 

Large populations of thistle or aster plants may become breeding grounds that create out of balance, excessive population numbers of Painted Lady butterflies.  In natural systems fire among other events control host plant populations thereby keeping insect population numbers in balance.

Within today's agricultural systems many natural events, like fires and deep biodiversity, are suppressed.

Once the hemp grower recognizes host plants for their importance and limiting roles they serve then overall ecosystem and pest balancing is easier to achieve.

Bird feeders around thistle or sunflower patches are one potential approach.  Birds utilize caterpillars as food.  Several bird feeders set up just inside your fence adjacent to a roadside thistle patch can serve to keep Painted Lady butterfly and caterpillar populations from becoming destructive and overwhelming.

Painted Lady caterpillars and butterflies are just one type of many native yet potential destructive 'bugs'.

Learning to recognize the 'bug' and understanding their lifecycles and host plants are all necessary components of an organic IPM program designed to maximize hemp production.  Rather than approach organic IPM from the perspective of 'how do we keep nature out of our hemp populations', we must figure out how to effectively integrate hemp cultivation into a balanced ecosystem in which we live.

Hemp cultivation operations existing 'in-sync' with a balanced surrounding ecosystem will be highly productive and efficient.  Organic IPM programs can be one of the hemp farmer's best grow partners.

Friday, November 5, 2021

Chlorophyll, Plant Age and UV light

Viola spp illuminated with UV 365nm showing chlorophyll in non-scarred, younger leaves reflecting red wavelengths

Chlorophyll is the plant phytochemical primarily responsible for converting sunlight into energy.  Plants take this chlorophyll generated energy and make carbohydrates to be used for growth.  This entire process of converting water, CO2, nutrients and light into carbohydrates (like glucose) is commonly known as the photosynthesis process, or simply 'photosynthesis'.

Viola spp. under full day spectrum light (reflecting green wavelengths)

Under full spectrum light chlorophyll absorbs all colors except green.  Reds and blues are absorbed by chlorophyll and utilized during photosynthesis.  Because chlorophyll doesn't absorb green under full spectrum light, the green wavelengths are reflected back away from the plants.  This is why most plants appear green to us in the sunlight.

Interestingly however, when illuminated with ultraviolet light, chlorophyll reflects red wavelengths back away from the chloroplasts where it is stored.  When a plant is illuminated with light in the UVa and UVb range the chlorophyll will reflect red hues.

I find interesting the fact that younger, fresh leaves usually reflect back a brighter and fuller red color when illuminated under UVa and UVb than do older leaves.  

As is with human skin, the cuticle and upper epidermis layers of a leaf can become damaged and scarred, a result of the sun's harmful UV rays, as well as from abrasion, pest and wind damage too.  Once the cuticle and epidermis is damaged, light in any form is restricted from entering the leaf to be absorbed or reflected by the chloroplyll.  Where young, fresh leaves may reflect deep red colors when illuminated with UV light, older, damaged leaves may be so scarred that the UV light cannot reach the chlorophyll.

Recognition of these principles can provide clues to a leaf's age, state of health, presence of pests, and other facets of the overall plant's growth cycle.

I find it interesting to take a portable UV light, wearing yellow UV rated safety glasses, and walk across the yard at night.  Plants that have evolved elaborate leaf cuticle and upper epidermis protection systems usually glow red under UV light as the leaf surface is usually free from UV and scarring damage.

Finally, not only do typical plants contain UV red reflective chlorophyll, but as you will notice when out at night with a UV light, algae and some moss covered surfaces will reflect red also.  Algae are photosynthetic eukaryotes and contain chlorophyll too! Mosses also contain chlorophyll.  Flower pots, wrought iron and other objects covered with a thin layer of algae will 'glow red'  at night under UV light.

You may ask, what does the understanding of chlorophyll's reflective color really mean to me?  As one small but important part of nature's life processes, an understanding of chlorophyll and light can help further learn about and understand the deep complexity of Nature's Languages.

Growing Hemp on a Green Roof? Is it Possible?

Growing Tomatoes on a green roof is similar in many ways to growing hemp on a green roof.

It is probable that hemp planted green roofs will become a norm in the future.

Hemp is a viable green roof crop with many positive economic and ecological attributes.  For instance hemp is a choice raw material in the making of paper and rope.

But what are the challenges of growing hemp on a rooftop?  There are many.  However, I believe that as in any green roof plant, hemp can be grown across a green roof system with proper consideration given to those challenges.

First, one must be familiar with the hemp plant and its growing requirements.  There are many varieties and cultivars of the hemp plant and each will have its own historically preferred conditions.  So knowing your hemp plant is important.

In addition to understanding hemp's growing requirements you must have a solid knowledge of organic hemp pest control.  I believe all rooftop grown hemp must be treated for pests using only organic integrated pest management (OIPM) principles.

Integrated, organic pest management with an emphasis on cleanliness and exclusion should be the management approach of all green roof operations, hemp or otherwise.  Green roofs are subject to constant winds.  Spraying chemical herbicides and pesticides on a rooftop could potentially expose adjacent neighbors to wind carried toxic compounds.

Irrigation is another issue to be resolved for hemp plants grown on green roofs.  Hemp, as all members of the Cannabaceae, are C3 plants.  C3 plants have evolved photosynthetic systems that are prone to support fast growth but also rapid desiccation potential.  Hemp must not be overwatered yet the plant also requires consistent water supply to its roots.

Before deciding on the best irrigation system for a hemp planted green roof there are other factors to be considered, including; heat tolerance, light levels, flowering requirements and more.  Some of hemp's optimal growing requirements can be addressed with either added mechanical systems or also with plant portability.

Temperatures on a rooftop can reach upwards of 150 degrees F or 66 degrees C.  Hemp won't survive long under those temperatures without a level of temperature mitigation.  Temperature mitigation options can include shade systems such as movable polypropylene screens or planting location strategies which take advantage of existing shade.

Other temperature options can include the possibility of utilizing a portable growing system that can be moved across the rooftop or off the rooftop as necessary.

Of course as with any mechanical system the rule should be; "the simpler the better ".  All mechanical systems can fail.  

Sunlight exposure and shading also have to be factored into flowering requirements.

Green roof winds can also be a serious challenge to fast growing and in some cases tall hemp plants.  Storms can quickly develop and hail or high speed winds may break, damage or topple hemp plants.

Despite all the challenges and considerations a rooftop grower of hemp must take into account, there are potential advantages to green roof hemp cultivation.

Free sunlight, rain, constant breezes and a measurable reduction of vectored pests may be benefits of rooftop hemp farming.

We will look at the many disadvantages and positive aspects of growing hemp on rooftops in future posts.

In the meanwhile, consider the issues associated with growing hemp on a green roof.  Talk with experienced green roof designers and growers.  As hemp becomes more excepted the popularity of hemp green roofs will only increase.

Wednesday, November 3, 2021

Hemp Pest Control; Begin With Cleanliness

 The basic number one rule of effective pest control for hemp cultivation is cleanliness.  Cleanliness in all stages of hemp growing is essential.

A clean hemp cultivation area requires;

1. Floors free of dirt & planting media, debris, trash or litter

2. Sterile planting media

3. Employee education concerning cleanliness practices

4. Shoe sterilization devices at entryways to greenhouses and production rooms

5. Regular trash receptacle maintenance and disposal practices

6. Proper use of disinfection media such as hydrogen peroxide and bleach

7. Education about pest vectors and implementation of immediate pest removal

8. Clean water program

9. Clean growing container program

10. Ongoing Integrated Pest Management (IPM) education and practice implementation

11. more

Clean growing practices is essential for a successful hemp cultivation program.

A good place to start is with the development of a cleanliness mission statement and written practice policy.  We will cover these more in the next few posts.