Can Plants Get Stressed?



There are two ways to answer the headline question: The easy way, and the right way. The easy answer would be simply saying: yes. On the other hand, to answer the question the right way, one should have a previous understanding of what stress really is.

Most of us have an innate understanding of the word stress. Lately, the word has taken on a mostly negative meaning, where stress began to mean an acute and chronic condition. It is true that a lot of people today suffer from stress in that way. Chronic stress then further worsens their condition causing health and mental problems - it is a vicious circle.

The true nature of stress has nothing to do with the previously described condition. It is simply a predetermined biological reaction to the surrounding conditions. It helps battle those conditions, and unless it becomes a chronic state, it is beneficial.

Plants, the same as humans, are often exposed to less than ideal conditions. Their response to stressful conditions is highly evolved. Unlike humans, plants can’t run from stress, therefore they are forced to stand their ground and fight as hard as they can - and do they fight.

Plants have evolved defense mechanisms against herbivores, fungus, drought, extreme heat and cold. All of those threats trigger unique hormonal responses, which in turn maximize the plant’s chance of surviving the stressful situation at hand. Recognizing that your plant is stressed and determining the cause of stress in a timely fashion gives you a chance to help the plant battle the stressor, and improve the situation.


Wilting is the most common plant response to stress. The reasons for wilting are many - insects, pathogens, inadequate watering, extreme heat, sudden change of conditions.

The most common reason for wilting is inadequate watering. If there were severe rains, or you just overwatered your plants, you should stop further watering until the plants recover and the soil dries up. On the other end of the spectrum, if there is not enough moisture in the land, plants will also wilt. It is important to check underground for moisture - somewhere near root depth, not just on the surface

If you are moving a plant from indoor conditions to outdoor conditions, there is a good chance plants will react to the added sun and wind by wilting. Building a light shelter to ease the transition will prevent it.

Bleached areas on the foliage in plants moved from indoor to outdoor conditions usually indicate sunburn. If so, the most bleached leaves will be the ones with most sun exposure. While plants will outgrow and recover from mild sunburn, you can prevent it by introducing the plants to the extra sun through a period of a few days or building a sun shelter.

Black areas on the foliage usually indicate frost damage - if the weather conditions for frost damage are present. Frost damage is most present on the exposed outer leaves. If you notice frost damage, wait for the weather conditions to improve and then remove the damaged leaves. Plants usually outgrow frost damage.

Ragged foliage is caused by harsh weather conditions as high wind or hail. While it is mostly only an aesthetic problem, in some cases, it can reduce the plant’s potential to fight off pathogens. Prune the ragged leaves to be safe.

Off-color foliage is usually caused by a nutrient deficiency. Using slow-release organic fertilizers takes care of any nutrient deficiency. If the discoloration persists, the plant's ability to absorb nutrients might be compromised. You should check if the soil's pH levels suit your particular plant - most plants need a pH level between six and seven.

Dried leaf margins are usually caused by improper fertilizer use or high winds. Fertilizer should be used according to the label, and if you can, you should use an organic slow-release fertilizer. In the case of wind being the problem, building a wind shelter or protecting the sensitive plant by planting them leeward of the more wind resistant plants will solve the problem

Burned foliage is a sign of chemical stress. It may be caused by pesticides or animal urine. You can try cleaning the damaged leaves with water and should prune any permanently damaged leaves.


Water stress is caused by a lack of water or an excess. In both cases, there will be noticeable wilting.

Nutrient stress is caused by a nutrient disbalance or an overall lack of nutrients. You will notice off-color foliage or in the worst case stunted growth.

pH of root zone must be maintained accordingly. The pH requirements depend on the type of growing you are doing. Wrong pH values cause your plant to gather nutrients at an inefficient rate. The symptoms are the same as in nutrient stress. Other than pH, root health can be affected by temperature variation in the soil. When growing indoors, make sure that the soil remains at indoor temperature.

Irregular light cycles when growing marijuana indoors causes reduced yield and can cause the manifestation of hermaphrodite plants. Be sure to respect the 18+ hours of light in the vegetative stage and the 12/12 light cycle in the flowering stage.

Plant tissue damage can be caused by environmental extremes such as hail or extreme wind, or by the mishandling of the plants. In most cases, the damage will be outgrown by the plant and is no reason to worry.

Environmental extremes are always bad for any plant. If growing indoors, be sure to maintain proper humidity and air circulation, as well as temperature. If there is a sudden change in the environmental conditions, the plant will react by slowing its growth and will have reduced yield in the end.