IPM: Yellowing Hemp Leaves? Lots of Reasons but Always Check pH of Soil and Water

 Yellowing of the lower leaves in hemp plants can be caused by several factors, and it's important to identify the correct one in order to address the issue effectively.

Yellowing Hemp Leaves caused by root zone pH being too high.

We try and provide the optimal growing conditions here at Arendell Hill Nursery in Tallahassee. Yet sometimes, no matter how intentional we are with organic nutrient application, good soil texture, adequate drainage, proper sunlight exposure and continual IPM we still encounter problems with plant growth.

Lately I've been seeing a bit of lower leaf yellowing on some of our container grown hemp plants. I know they have been properly watered and fertilized however the yellow seemed to be persistent.

There are many cultivation variables known to be responsible for yellowing hemp leaves.

Here are some common causes:

1. Nutrient Deficiency: This is often the most common cause. In particular, nitrogen deficiency can lead to yellowing of the lower leaves because the plant moves available nitrogen to support new growth at the top. Other deficiencies that can cause yellowing include potassium, phosphorus, and magnesium.

2. Overwatering or Underwatering: Both of these can stress the plant and cause yellowing. Overwatering can lead to root rot and oxygen deprivation, while underwatering can cause the plant to become dehydrated.

3. pH Imbalance: Hemp prefers slightly acidic to neutral pH levels (around 6-7). If the pH is too high or too low, it can lock out essential nutrients and lead to yellowing.

4. Poor Drainage: If your hemp plant is in a pot or soil with poor drainage, it can lead to waterlogging and oxygen deprivation for the roots, causing leaf yellowing.

5. Pests and Diseases: Certain pests and diseases can also cause leaf yellowing. For instance, fungus gnats can damage the roots and lead to yellowing of the lower leaves.

6. Temperature Stress: If the temperature is too high or too low, it can cause stress to the plant and result in yellowing.

7. Light Burn: If the plant is exposed to too intense light, it can "burn" the leaves and turn them yellow.

In our case the yellowing was a result of our irrigation water's naturally high pH of around 8.0 to 8.5. High pH water can, as mentioned above, prevent the hemp plant roots from taking up nutrients, even if those nutrients are available and exist in plentiful quantities within the hemp plant's root zone.

Irrigation pH balancing involves taking into account acidic rainfall amounts and then pH of natural irrigation water. During droughts, when more higher pH irrigation water from the well is used, more 'pH Down' (a water acidifier we use) must be added to irrigation to keep the root zone pH around 6.0-6.5.

When we have periods of significant rainfall, the hemp plant's root zone is less likely to exhibit a higher pH simply because we are using less well water.

Portable, battery powered pH meters are an important tool for Florida hemp growers (and any gardener for that matter). Here is a link to the pH meter we use.

Remember, identifying the exact cause requires observation and sometimes a process of elimination. Always consider the overall growing conditions including light, temperature, humidity, and the plant's watering schedule. If you're growing indoors, you can more easily control these factors compared to outdoor growing.

IPM: Species Biodiversity in the Garden Promotes Effective Integrated Pest Management Results

 We grow many Florida native plant species alongside our FAMU pilot project hemp (x Hepius & x Master Kush).  

The native wildflower, Rudbeckia hirta growing next to a FAMU pilot hemp x Hepius 

We've found the richer the growing area is with respect to plant species biodiversity, the more beneficial insects we notice foraging or taking up communal presence in the garden.

Hemp can be negatively affected by caterpillars and here in North Florida we have so many different types of caterpillars throughout the year.

Parasitoid wasps are helpful in controlling caterpillars by laying eggs in the caterpillar, using the living caterpillar as a larval host.  Parasitoid wasps are often attracted to the growing areas because of the presence of mint plants, like the native Monarda punctata.  Wildflowers also offer beneficial insect attraction potential.

In our hemp and food gardens, native plants and wildflowers are important components of our Integrated Pest Management (IPM) program.  We believe diversity in species not only plays an important role in pest management but also helps create high quality, unique niche plant product through environmental and epigenetic factors.

IPM is a comprehensive, environmentally safe approach to managing pests. It integrates different pest control methods to achieve long-term pest management solutions while minimizing the harm to people and the environment. Biodiversity in plants plays a critical role in this approach for several reasons:

1. Habitat for Beneficial Insects and Organisms: Different plant species attract different types of insects and other organisms, including those that are beneficial for pest control, such as ladybugs, spiders, and predatory mites. These beneficial insects and organisms feed on pests, helping to keep their populations in check.

2. Resilience to Pests: A diverse garden with a variety of plant species can be more resilient to pests. If a pest does become a problem, it is less likely to wipe out an entire crop because different plants are often susceptible to different pests.

3. Disease Resistance: Just as with pests, different plant species have varying degrees of resistance to different diseases. Having a diverse range of plant species can help prevent the spread of disease in a garden or agricultural field.

4. Crop Rotation and Intercropping: These are two techniques that rely on plant biodiversity. Crop rotation involves changing the type of crop planted in a particular area each season, which can help prevent pests and diseases that favor specific crops. Intercropping, on the other hand, involves growing different types of plants together, which can help deter pests.

5. Healthier Soil: Biodiversity also contributes to healthier soil. Different plants contribute different nutrients to the soil and have different effects on its structure and microbial life. A diverse range of plants can thus help maintain a healthy, balanced soil ecosystem that can contribute to pest management.

6. Cover Crops and Green Manures: Some plants can be used as cover crops or green manures. These plants are grown not for harvest but to improve soil health, suppress weeds, and manage pests and diseases. They can be an integral part of an IPM approach.

In conclusion, plant biodiversity is a crucial component of integrated pest management. It helps create a balanced, healthy ecosystem that can naturally keep pests in check while also providing other environmental benefits.

Organic Hemp Cultivation Pest Plant Alert, Lamium amplexicaule aka Henbit

 Henbit, Lamium amplexicaule, is a purple flowered non-native groundcover with an aggressive growing habit renown for taking away native plants growing space.

Lamium amplexicaule, Henbit and Organic Hemp Cultivation

Once established, henbit is difficult to eradicate.

There are two main species of Lamium in Florida, henbit and purple deadnettle, L. purpureum.  Purple deadnettle differs from henbit visually with purple hued leaved near the plant top, or apex.  Henbit also can be usually recognized by the way it's leaves directly clasp the stem.

Although diminutive, lacy in appearance and a rather pretty groundcover, henbit might be thought of as harmless yet the opposite is true.  It is estimated by many ecological experts that almost half of all native plant species are in population decline due to loss of habitat as a result of competition from non-native species.

Lamium competes with native groundcovers for water, growing space, nutrients and importantly can be a host for hemp or other crop damaging pest insects, including a number of nematode species such as Ditylenchus spp., Heterodera spp., and Meloidogyne spp. along with a number of viruses (including Arabis mosaic virus) and fungal pathogens.

Controlling Lamium spp. in rowcrop cultivation settings can be difficult.  This weedy plant is often thought of as an annual species however it may often behave as a biennial in Florida climates.

I prefer to help establish lyre-leaf sage, Salvia lyrata or turkey tangled frog fruit, Phyla nodiflora along with a host of much better suited native groundcovers that support beneficial predatory insects, beneficial pollinators and positive biological pest management.

Personally, if I see henbit growing in the hemp cultivation areas the plant quickly becomes a candidate for pulling and mechanical eradication/composting.  Better safe than sorry when growing hemp.

Florida Organic Hemp Cultivation and Fungi Based Integrated Pest Management

 Blue oyster mushrooms, Pleurotus sp., are an important part of our Integrated Pest Management program here across Arendell Hill nursery.

Oyster mushrooms are an integral part of Organic Hemp IPM program here at Arendell Hill

Oyster mushrooms help clean stormwater and detoxify any contaminants that find their way via wind, rain or drift into the garden. 

Interestingly, many fungi are capable of absorbing complex carbon chains found in the environment and converting them into carbohydrates for their own growth.  

Mycoremediation, as the mushroom's decon process is commonly referred to, has been shown to be an effective way to support hemp cultivation area cleanliness while helping to ensure pure surface water. 

Additionally, mycobooms, which are a mixture of hay and fungal spores can be used to contain and cleanup most types of contamination spills and can be an effective pollution control management tool.

Because our cultivation areas are organically managed and free of pesticides and herbicides, the oysters in our garden are usually free of contamination and may also end up in our kitchen for dinnertime sauteing.

For decades, fungi have been successfully used in many organic-focused integrated pest management programs.  Additionally, mushrooms are fun to grow.  Cultivating oyster mushrooms as a companion species to hemp is just one, but an important part, of Arendell Hill's organic hemp integrated pest management program.

Millipedes, A Beneficial Integrated Pest Management Partner for Florida Hemp Cultivation

 Millipedes are an important #IPM partner for our #hemp cultivation plot. 

These scavengers prefer to eat moist leaves and plant litter.  

They do a marvelous cleanup job here at Arendell Hill, mulching up leaf litter and then fertilizing the soils with plenty of organic droppings.  

Millipedes help control fungal and algal explosions by keeping damp leaf debris accumulation to a minimum amount. These small arthropods are constantly foraging here.  I see them occasionally during the day but at night they are visible (with a UV light) almost everywhere across the ground.

Millipedes have 2 legs per segment side while centipedes have one.

Consider your cultivation area lucky if you are fortunate enough to have a substantial population of these beneficial arthropods.

#millipedes #IPM #beneficialinsects #organic #floridahemp

Surinam Cockroach and Organic Hemp Cultivation

 These photos are of the Surinam burrowing cockroach, Pycnoscelus surinamensis, also known as the greenhouse cockroach, an exotic pest insect originally found in south to southeast Asia.

Surinam Cockroach, a potential key pest for hemp plants

Though preferring tropical or subtropical climates, the Surinam cockroach is now recognized to thrive in temperate zones also.

Surinam cockroach is often considered an economic risk pest especially in greenhouse settings. This roach is susceptible to solar desiccation and usually ventures out at night, where in the greenhouse it has been documented to eat tender buds and plant tips.

Surinam cockroach is one of the few insects that can commonly reproduce through female cloning without male sperm. This process is referred to as parthenogenesis. Studies have shown that multiple generations of the Surinam cockroach exist in the same location without the presence of even one male.

Surinam Cockroach in the hemp garden

Because the Surinam cockroach can damage tender buds and plant tips, any roach favorable habitat such as piles of wood, trash or stacks of nursery pots should be cleaned and either disposed of or organized appropriately.

I try and encourage bird presence in areas where I've identified this pest insect as birds will prey on this insect.

Understanding the preferred habitat and taking steps to integrate predatory management approaches in the hemp cultivation plan can lead to a successful Surinam cockroach control program.

Organic Florida Hemp Cultivation, Identifying Crop Pests with UV Light

Evolution has equipped many insects with a sublime ability to camouflage themselves. 

Pest Insects may remain hidden under most light wavelengths as shown here on a greenhouse lemon balm plant.

Insects may stay hidden under daylight wavelengths too.

Evolution has equipped many insects with effective camouflage appearances

Interestingly and importantly for the grower, ultraviolet lights used at night that produce illumination in the wave range between 300nm and 400 nm can often illuminate otherwise camouflaged pest insects.

UVb light can assist in identifying the presence of crop pests

Pest reconnaissance of crops in cultivation areas including those in row plantings and in the greenhouses can be conducted at night often with successful results for insect identification efforts.

Insects, plant damage, and even chlorophyll containing algae and cyanobacteria can be identified at night by examining plant stems, leaves and flowers using UVa and UVb lights. Many insects react to UV light through florescence of phosphors in their exoskeletons. Chlorophyll on the other hand under UVb absorbs all light waves except for 'red' wavelengths which are reflected back.  Algae growing across cultivation areas can easily be identified using UVb light.

Not all insects that glow under UV light are considered pests.  Potentially beneficial organisms such as stick insects, millipedes and even anoles can be easily spotted using UVa and UVb flashlights.

My personal favorite light for night insect surveillance are lithium rechargable, well built LED units with UVb filters.

Though the grower may not spot all pest insects on their greenhouse or row crop plants, chances are any key pest infestation can be quickly identified.

Warrior Beetles and Organic Hemp Cultivation

 Warrior beetle.  Good insect for hemp cultivation.

Warrior beetles are excellent predatory pests to have in the Florida organic hemp cultivation area.

Pasimachus sp., plays an important role in our organic integrated pest management program. 

Pasimachus has a never ending appetite for pest insects in the garden! What a great predatory beetle. 

#IPM #organic #hemp #Florida #Floridahemp

Florida Hemp Cultivation Bed Preparation

 Hay arrived yesterday for spring gardens.

Hemp cultivation is made easier with a quality mulch such as organic hay.

Excellent quality organic hay is useful as a mulch in the hemp garden, usually a bit more pest free than our mulched leaves.

We do mulch and reuse our leaves too however we find hay to be a favorite for maintaining soil moisture, keeping soils less compacted and not as hot, for buffering pH and contributing to overall organic matter content.

Hay is easily to spread, lightweight and readily & sustainably available on a local basis.

Planting Bed Prep for Spring Organic Hemp Crop

We began breaking soil and adding mulched organic matter from the Arendell Hill site in preparation for spring hemp planting.

In addition to the mulched organic leaf litter bird feeder platforms are now added to the cultivation area. Arendell Hill is a favorite foraging location for all types of birds, from large raptors to small songbirds. 

We enlist the birds to protect our hemp plants. Songbirds work efficiently in eating certain pest insects such as caterpillars, beetles and bugs. 

Planted around the base of the bird feeders are native plants and wildflowers such as spotted bee balm, Monarda punctate. M. punctate attracts predatory wasps and other beneficial insects such as the assassin bug. Predatory wasps and assassin bugs control many cannabis crop pests through a variety of methods.

Arendell Hill Nursery employs a complex and highly integrated matrix of natural and organic pest control approaches. An understanding how the cultivation site's ecosystematics function allows the grower to take advantage of each and every biological, meteorological and geological variable for growing amazing quality CBD and CBG rich flowers. 

Asian Lady Beetles and Organic Hemp (Cannabis) Cultivation

 I've been seeing Asian lady beetles, Harmonia axyridis, almost everywhere lately (early February 2022).

Asian Lady Beeetle, Harmonia axyridis, exotic insect and Organic Hemp Cultivation

Though they do little direct harm to cultivation (they do eat aphids) these exotics can cause serious nuisance issues around plants and especially in buildings. They certainly are not my preference for natural IPM across the hemp farm as they compete with native lady beetles.

Asian Lady Beetles on pepper plants at a local Tallahassee Nursery

Mostly, I tend to ignore them because they do not rise to the nuisance level of a 'key pest'. Beware though the Asian lady beetles can bite humans and they do leave a yellowish staining, foul smelling excretion when congregating in and around building windows.

Asian Lady Beetles should be monitored however across the hemp farm for potential damage

All in all, I'd rank them as a low species of concern, one worth notation (I certainly would not want too many of these insects foraging in plant flowers and buds) but not worth immediate worry over, across the hemp farm.

January Fungi, Florida Hemp Cultivation Integrated Pest Management

 Fungi play an important part in our integrated pest management program. Tracking fungi appearance and location is an important part of the organic matrix at Arendell Hill. January fungi under live oaks, coral fungi, Ramaria sp. considering R. formosa. Leon County

Tracking fungi across Hemp Cultivation area helps us understand the role fungi play in pest control