Environmental Stresses and Their Effects on Cannabis Plants
Though the word has mostly negative connotations, stress isn’t all bad for a cannabis crop. Some pot seed growers intentionally stress their crops to accelerate growth, maximize yield, and strengthen the plants’ resistance to disease. However, some types and levels of stress may have detrimental effects. Here, we’ll look at some of the most common stressors for cannabis plants and some ways to minimize the effects of stress.
Water Stress From Over- Or Underwatering
Experienced marijuana seed cultivators know that watering too much or too often is just as bad as a continual drought. Over or underwatering plants may cause their leaves to become discolored, wilted, and curled. When plants are overwatered, their roots can’t get the oxygen and nutrients they need. Overwatering-related stress is a common cause of growing problems but underwatering is equally concerning, especially in hotter climates like in Arizona or Florida.
Nutrient Stress Related to Over- or Underfeeding
Many cannabis seed growers, especially those doing it for the first time, run into problems caused by over- or underfeeding. Your cannabis plants should not receive any more nutrients than they can handle. Similarly, plants can become stressed when they don’t get enough nourishment or when the balance of nutrients is wrong. Nutrient-related stress brings on various plant problems, from stunted growth to discolored leaves. Overfeeding may also attract bothersome bugs and other intruders.
pH Stress
For optimal growth, cannabis plants need a nutrient solution or soil mixture that’s pH balanced. If the growth medium’s pH level is a bit off, the plants can’t absorb nutrients even if they’re present in the right quantities. Inaccurate soil pH leads to major deficiencies and growth problems, and pH-related stress may cause issues such as root burn.
Light Stress
Marijuana plants are sensitive as far as lighting quality and quantity are concerned. When plants do not get enough light, they simply cannot reach their full growth potential. Low light during the flowering stage is sure to lead to a substandard harvest.
When cultivating cannabis, in Missouri or Utah, it’s crucial to put the plants on a consistent light cycle. Plants should get 18 hours of steady light during the vegetative stage, and during flowering, they should be on a 12/12 light/dark cycle. When light cycles are inconsistent, the plants become confused.
It’s important not to interrupt the dark portion of the light cycle, as plants are easily stressed during the flowering stage. When the lights-off period is broken, the plants will regress from the flowering phase into the vegetative stage. This adversely affects the plants’ health, growth, and yield.
Light Stress Weed
Light Stress Autoflower
Stress Out Weed Plants
Stress After Tissue Damage
Slight damage to a cannabis plant’s branches or leaves is typically no cause for concern, as these plants are relatively resilient. In some instances, minor tissue damage may strengthen a plant’s disease tolerance, but constant stress has negative effects. When plants spend all their energy on regeneration, there’s not much room left for growth.
Root Damage and Stress
Cannabis plants absorb oxygen and nutrients through their roots, which makes root health crucial. Stress and damage caused by temperature shifts, physical damage, light, mold, and bacteria will substantially affect plants’ growth. Generally, growers should keep the root system at or near room temperature. In outdoor grow ops, it’s quite concerning when pots get hot from the sun’s rays. Root rot and mold are other common root problems, and they typically occur when drainage is poor. Here, the roots can’t get the oxygen they need.
Environmental Stresses
If you’re comfortable within the growing environment of your Tennessee backyard garden, your plants will likely be at ease as well. Any extreme condition, such as excessive humidity or temperature shifts, may cause stress to the plants and decrease crop yield. The grow room’s temperature should be kept at a constant, comfortable level, and extreme, sudden temperature changes should be avoided. Proper ventilation and circulation are other factors worth considering. When the grow room has good air circulation, you’ll avoid the high humidity that often leads to mildew and mold growth.
Disease and Pests
Aside from insects and animals eating the plants’ leaves and causing tissue damage, these pests can also spread diseases throughout a crop or make plants more susceptible to illness. Plants can typically recover from infestations if the situation is quickly addressed, but diseases pose other problems. Fungal infections such as botrytis or powdery mildew are controllable once they’ve infected the plants, but viruses, root pathogens, and other invasive diseases are almost impossible to eradicate once they’ve taken hold.
Cloning Stress
For cultivators, the primary goal for cannabis plant cloning is to get the cuttings to take root. Though rooting can be done manually, there are a few useful tools to rely on. For instance, some cuttings won’t take root quickly, but with a dab of rooting gel and some minor environmental changes, things will take off.
Some growers wonder if they can use cuttings from flowering or fully mature plants. Yes, it’s possible to take cuttings from cannabis plants at almost any growth stage after germination. However, it’s usually a good idea to wait for the plant’s structure and root system to develop. If cuttings are well taken care of, they should survive and even thrive.
Should You Intentionally Stress Cannabis Plants?
Though there’s no disputing that stress makes cannabis plants more potent and resilient, it’s important to tread lightly. Intentional stress may affect the quality of the yield, and because of the risk involved, such methods aren’t commonly used by commercial growers.
Without the ability to accurately assess a plant’s reaction to stress and strain, a novice grower should concentrate on providing plentiful nutrients and a favorable growing environment. From an economic standpoint, reducing cannabis plants’ stress improves yield consistency and allows dispensaries to offer a uniform product. To compete with the pharmaceutical industry, cannabis dispensaries must control the quality of the product, and the process begins at cultivation.
Sometimes, A Little Stress is a Good Thing
While cannabis is a very versatile plant, it is sometimes sensitive. It’s highly reactive to the environment in which it is grown, and it may thrive or wilt depending on prevailing conditions. When cultivating cannabis, it’s just as important to focus on good stress as it is to prevent detrimental stress.
As mentioned previously in our guide, stress may help cannabis plants if it’s properly introduced. Good stress raises plants’ endurance and helps buds grow bigger. The best plants for cloning are the ones that can survive and thrive under controlled stress. In the following sections, we’ll discuss some of the best ways to stress cannabis plants.
Airflow
This is a common way to put cannabis plants under controlled stress, and many growers do it without realizing the benefits of the practice. Using fans to keep leaves and branches moving causes constant, yet slight stress to the plants’ stems, making them grow stronger and thicker.
Cold Exposure
Although it might sound extreme, exposing marijuana plants to cold during the final days of the flowering stage may have positive effects. For the best chance at success, keep the grow room’s temperature at 50 to 60 degrees Fahrenheit during the dark portion of the light cycle. The fluctuation between warm, light-filled days and cold, dark nights mimics the plants’ natural cycle and improves their metabolism, leading to accelerated resin production.
Low-Stress Training
Low-stress training or LST is a way to encourage the directional growth of branches so lower portions of the plant can get more light. When LST is done during the plants’ vegetative stage, it makes the stems grow thicker, which helps get nutrients to the leaves and the tops during flowering. Low-stress training keeps plant heights manageable, making them bushier, more compact, and easier to grow.
Subjecting the plants to LST may increase terpene levels, but too much stress will reduce crop yield and quality. An easy way to stress cannabis plants is to pinch branch stalks or reposition branches that don’t get much light. Pruning low-hanging branches during flowering will help the plants focus precious resources on the colas, which will increase terpene production.
Stress and Hermaphroditism
While excessive stress sometimes leads to hermaphroditism in cannabis plants, the tendency is typically dictated by a plant’s genetics. Growers should avoid significant stresses that may induce plants to develop hermaphroditic tendencies.
For instance, plants may grow fine outdoors, but if they’re moved inside, the stress may cause them to exhibit the reproductive traits of both genders. If this occurs, the only real option is to remove any male flowers as quickly as possible. This prevents plants from pollinating themselves. You should also separate these plants from the rest of the crop to eliminate other pollination risks. Don’t use seeds from these plants, because subsequent generations may exhibit similar traits and the tendency to self-pollinate.
Cannabis is a Resilient Species
Though certain conditions are conducive to the growth of cannabis plants, they have a surprising ability to respond to temperature fluctuations, tissue damage, and other environmental stressors. For instance, the ideal grow room temperature is 60-80 degrees Fahrenheit, but plants can recover from temperature fluctuations with generous watering, protection from heat, and supplementation with seaweed extract. This restarts the nutrient absorption process, which may stop when the soil runs dry.
Cold temps are another stressor for cannabis plants. When these plants reach 32 degrees or below, the water inside the cells freezes and causes severe damage. Though frost is a cause for concern, if the plants can slowly thaw, they may only have slight damage. Protecting outdoor crops with cloths or a portable greenhouse will help to minimize shock and tissue damage.
For instance, strains such as Northern Lights, Critical Jack and Killer Queen are all valued for their easy cultivation and high tolerance to stress. Conversely, strains like Headband, Maui Wowie, and Thai Passion are somewhat more challenging to cultivate. Many strains find it difficult to navigate stress due to their size (which increases the risk of indoor burning) and the inability to defend against mold growth and pest infestation (which may be made worse with overwatering).
Plants Adapt to Their Environment
Though the origins of cannabis are uncertain, we’ve found that different strains arose in certain climates and that the plants’ grow patterns demonstrate their adaptability. For instance, Indica strains first arose in the variable climate found in the Hindu Kush mountains. Therefore, these strains have developed habits that reflect their environment. With smaller plants and shorter growing cycles, these strains are more likely to survive to maturity even in the cold.
Conversely, Sativa strains originated in temperate climates near the equator. These strains developed growing habits that were well-suited to the hot, long summers, and they typically grow fluffy, large buds that cover the length of the stems. For these reasons, Sativa-dominant strains are better equipped to withstand high temps, but they may not do so well in wet, cool environments.
Cannabis plants produce seeds as a last-ditch effort to perpetuate the species. When plants become stressed, they may turn hermaphroditic as a means of self-preservation. If female plants are in a high-stress environment that’s not conducive to their survival, seed production helps ensure that subsequent generations will carry the same genes. Sometimes, female plants produce additional colors or trichomes to protect themselves from the harsh UV-B rays of the sun. These plants may develop more colas when trained with ScrOG methods.
In Closing
Stress is a double-edged sword as far as cannabis cultivation is concerned. In the right situation, it can be helpful; however, too much of a good thing can be a bad thing. The most crucial step is to find the right balance of light, water, and nutrients, and to apply it consistently.
Professional American weed seed cultivators use intentional stress to strengthen plants and attain high yields, but these approaches should be used with caution. If a novice grower fails to pay attention to the crop, or worse yet, overdoes it, the plants will suffer.
Cannabis is a resilient, hardy plant and is usually easier to cultivate than most people think. After all, that’s why it’s commonly referred to as weed! Occasional periods of stress on a crop shouldn’t be a cause for worry, but it’s important not to take things too far. By avoiding consistent or significant stress, you’ll ensure that your precious cannabis plants receive everything they need to grow and thrive. Contact us today to get the best selection of easy beginner seeds to get you started on the right foot.
