Outdoor marijuana growing – Plant problems

I love marijuana nutrient deficiencies

Marijuana plant problems

As a cannabis grower, the ability to spot sick plants and diagnose their ailments will be of great importance to you. This is particularly so with marijuana, since the one thing you normally cannot do is ask for external help. This article will help you to recognize deficiencies in your marijuana plants and diagnose and remedy the situation.


Remember that it is possible for your marijuana plants to have too much of a good thing, as well as not enough of the things that they need most. The first step is to think about how balanced your plants’ diet has been (N-P-K) and then check the PH of both the soil and the water that you’re feeding to them. If those both check out but your plants are still showing signs of distress, then your problem may be sunlight, since you can control the PH and the nutrient regimen. On the other hand, if your marijuana plant is ailing, sunlight is plentiful and the water you’re feeding it is okay, then you have nutrient issues.


Nutrient Deficiencies

The most basic problems with your marijuana plants will be that certain nutrients are unable to be absorbed by the roots, or are not extant in the soil itself. Soil amendments are great in this situation because they provide the nutrients that a plant needs; however, recognizing which nutrient is not being absorbed may be difficult. There are signs to look for, but even these may not suffice since certain deficiencies will produce similar symptoms. The following are some helpful hints for detecting which nutrient may be deficient in your plants’ diet.


Nitrogen (N) 

Nitrogen plays a very big role in the life of your marijuana plants. It is responsible for production of chlorophyll- photosynthesis – and also amino acids, which are the building blocks of proteins. Nitrogen deficiencies usually start on the lower to middle part of the plant and mostly affect older leaves. Marijuana plants that exhibit nitrogen deficiencies tend to be green on top, but the leaves yellow toward the bottom. This is especially common once your plants have begun to flower since the plant is utilizing its cache of nutrients stored in its leaves. If your marijuana plant is in the vegetative growth stage then this is a problem since the yellow leaves are no longer aiding in harnessing the power of the sun to grow.


There are a few ways to rapidly increase your plant’s intake of nitrogen. One of them is to use blood meal. Other sources of nitrogen are dried blood, cottonseed meal, bat guano (or bat excrement), fish meal (or fish emulsion), as well as worm castings (again, excrement). All of these are available at any good gardening store and definitely online. There are also chemical amendments that are quite easy to find at any store, for example, Miracle-Gro or other brand-name plant foods. Nitrogen deficient plants usually recover in about a week, but sadly, the affected leaves will never recover. They will drop off, but new ones will replace them. It is important to always check the pH before and after adding soil amendments since some of them will cause fluctuations in your pH.


Phosphorus (P) 

Phosphorus is beneficial to your marijuana plants in many ways. It aids in root growth and strengthens the leaves and stems. It is also very influential during flowering as it helps to germinate seedlings. It is typically needed in large amounts, and most soils that are N-P-K balanced will include heavy doses.

Phosphorus deficiencies cause the plant to seem weak and life- less and will slow the plant growth. The edges of your marijuana plant’s leaves will be brown or very dull in color and curl inwards. Some cannabis growers have noticed that whenever the temperature is cold, usually early or late in the season, their plants have a hard time absorbing the phosphorus in the soil, which calls for a larger infusion than usual. Other factors that contribute to phosphorus deficiencies include cold, wet soil or very alkaline soil.


Any organic or store-bought fertilizers or plant foods that have phosphorus in them will fix a phosphorus deficiency. Make sure though that the N-P-K ratio is above five. Some all-purpose plant foods, such as Miracle-gro, will also work- although make sure that you blend at half the recommended amount since too much may be toxic to your plants. Bonemeal is another good source of phosphorous, as are the castings of bats and worms. Another suggestion, if you can find it, is crab shell or crab meal, which some growers swear by as an all-purpose fixer, but especially for phosphorus deficiencies.


Potassium (K)  

Potassium, the last of the major soil nutrients, plays a big role as well. This nutrient helps your marijuana plants with disease resistance and water respiration, and assists the leaves in their photosynthesis production and conversion. Potassium also helps to circulate water throughout the entire body of the plant and is necessary during both the vegetative growth and flowering stages.

Having too little potassium in your cannabis plants may cause their leaves to grow very slowly and seem to be scorched around the tips and edges. Your plants may bend too easily and become broken by the wind. The more mature leaves may show different patches of color (mottle) and turn yellow between the veins, followed by entire leaves that turn dark yellow and die. The plants overall growth slows down and finally and most damaging, your flowering will be delayed.


Potassium deficiencies are relatively easy to fix because this nutrient is absorbed by your plants very quickly and easily under a variety of PH conditions. If you are using store-bought fertilizers, simply adding some that contains potassium should solve your problem relatively easily. Some organic fixes include: wood ashes, kelp meal, granite dust, or sulfate of potash.


This list is by no means exhaustive, but many of the problems you encounter with your plants will be nutrient-related and if your soil has these three basic elements, your plants should be healthy enough to harvest. A more complete list of additives is given in this section of the website. With most of these solutions, you’ll see results about a week after adding the amendments. Early detection is always the key.

One quick note about diagnosis: since some of the deficiencies are very similar to one another a good idea might be to flush the soil with water before adding anything. Sometimes your deficiency is actually caused by having too much of a nutrient. For instance, having too much potassium can prevent the absorption of iron. Always flush, then PH test, add, then test again. Another reason to test the PH is because almost anything added is best absorbed when the PH level is as close to seven as possible. The best way to add any nutrient is to foliar feed the plant by making a tea and spraying the leaves. Never do this at the hottest part of day. Either early in the morning or just after the sun sets are the best times.

If you order marijuana seeds from my webshop and you get problems with pests or diseases, I’m here to help you. There are guides about plant care where all pests/diseases are discussed and you can contact me by mail. Please like or share this article


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One thought on “Outdoor marijuana growing – Plant problems

  1. Pingback: Outdoor deficiency | Exclusivebeach

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