Thursday, July 7, 2011

Mega Feature: Time to Talk Nutrition

     Nutrients: the building blocks of life, no matter what organism you may be. Humans get their nutrients through food and vitamins; plants get theirs primarily through the soil. As gardeners, it falls onto us to ensure our plants receive proper nutrition. Unless your backyard has exceedingly rich and loamy soil, pay close attention to find out how to maximize your plants' growth, from the nutritional perspective.

Srpayin Away! It's time for the weekly foliar feed

     What you see above is my preferred method of fertilizing when the soil is high in organic material, simply known as foliar application, or "leaf application". For the last couple years I had been feeding my plants exclusively through the roots. I knew I had to change this year, as the compost I had ordered was quite high in wood chips and other organic material, meaning it would require additional nitrogen to be broken down into rich soil. Because of this, nitrogen entering the soil with water (during a typical root feeding) would not all be utilized by the Cannabis plant. So, instead of having my plants compete with organic material for precious Nitrogen, I switched to foliar feeding. If your soil doesn't hold water particularly well, or is high in organic material, consider foliar fertilizing a viable option to deliver the nutrients your plants need.

     Now let's go into a little more detail, and explore what really makes up a balanced plant diet. Please note that if you have rich soil, either through your own natural backyard or by adding topsoil and other mixes, you will likely not encounter problems with lesser nutrients. Problems concerning Nitrogen and Phosphorus are far more common, and will probably make up the majority of your nutrition issues.

     Nitrogen(N)- This guy is the basis of all plant growth. Plants with sufficient Nitrogen will look dark and healthy, with flexible branches and no leaf discoloration. Plants deficient in Nitrogen may have stunted growth, light colored leaves (ranging from lighter green to yellow, the less green the less healthy), and red, brittle branches. Excess Nitrogen may result in extremely dark and unhealthy leaves.

Leaves of all these colors (too light and too dark) can indicate a Nitrogen problem

     Phosphorus(P)- Phosphorus goes hand in hand with Nitrogen; N causes growth, P causes the bloom. Although Phosphorus is needed throughout the grow season for optimum plant health, it becomes much more critical in the final 2 months of the season, as your plants begin to bloom. The right amount of P during the vegetative phase will keep your plants growing healthy, and the right amount during your bloom phase will help produce a larger crop.

Lack of Phosphorus during the growth phase indicated by dark leaf pigmentation

     Potassium(K)- Potassium is involved with water status maintenance as well as some cellular activities. K is needed to maintain the overall health of the plant, and lack of it can reduce both quality and quantity from your Cannabis specimen. However, too much Potassium can interfere with the uptake of other lesser nutrients, including magnesium, manganese, zinc and iron as well as calcium. 

Leaf discoloration as well as a weak and brittle stem indicate a Potassium deficiency

     Magnesium(Mg)- Magnesium is a component of the chlorophyll pigment, and is involved with many enzyme actions as well. Simply put, Mg is not a major element in the gardening process, but it necessary to maintain a healthy specimen. Many nutrient mixes will have small amounts of Magnesium as well as other lesser nutrients to ensure you feed your plant a balanced diet.

Leaf discoloration and curling in an otherwise healthy plant may indicate a Magnesium problem

Zinc(Zn)- Zinc is another lesser nutrient, and plays a similar role in enzyme reactions to Magnesium and Manganese. Like Mg, Zinc can be locked out at high levels of pH, so make sure your fertilizing water is between a pH of 6 and 7. Foliar feeding completely bypasses the roots, though, allowing you to avoid dealing with pH concerns. 

A true Zinc deficiency, complete with extremely light coloring between the veins of the newer leaves

Sulfate(S)- Sulfate is involved in plant respiration, as well as synthesis and breakdown of fatty acids. It's another lesser nutrient, like Potassium, Magnesium, and Zinc, but its role is just as important as Nitrogen or Phosphorus. If you have a Sulfate deficiency, you will notice yellowing leaves that begin to curl downwards, as well as a woody stem and an overall sickly looking specimen.

A woody stem, discolored leaves that curl downwards, and purplish upper stems point to a lack of Sulfate

Iron(Fe)- Although a lesser nutrient, Iron is critical for plant health and development. It is responsible for maintaining several different functions, including the management and uptake of Nitrogen and Phosphorus. Similar to other nutrients, Iron becomes unavailable to your Cannabis plants if the pH of the water or soil is too high. Again, you can foliar feed to bypass your pH problems, as it may be a problem

Lack of Iron can be observed when new growth is discolored between the veins

Manganese(Mn)- Another lesser nutrient, Manganese regulations many enzyme functions and is an important component to a healthy Cannabis specimen. Like all of the other lesser nutrients, Mn becomes unavailable if the pH is too high. Lack of Mn can result in blotchy leaf coloration and even leaf necrosis (dead spots of tissue on leaves), as can be seen to the right.

Spotting and Necrosis, as well as general leaf discoloration all point to a Manganese problem

**Remember, lesser nutrients will show their first symptoms on younger leaves and progress to the whole plant. Always guide your actions by how the new growth looks towards the top of the plant.**

     Phew. Seems like a lot to take in right? While all of the information above is helpful to know if you want a succesful harvest, it is not all neccesary to memorize. The two most important nutrients are Nitrogen and Phosphorus; if you can keep these two balanced at proper levels throughout the grow season, you will be very succesful. The lesser nutrients require much less mainteance, as a good fertilizer mix will provide you with sufficient amounts of said nutrients. 

     The final aspect of a balanced plant diet are hormones. These aren't the hormones bodybuilders use, or the ones put in your cows to make bigger burgers, these hormones increase plant growth and vitality. There's only one brand I know of, SuperThrive, and you can find it in the garden section of a Lowe's or Home Depot, or any garden specialty store. Seen below, between my other main fertilizers, is a bottle of SuperThrive.

Potent fertilizers and hormones; the backbone of any successful grow, available wherever garden products are sold
     Until next time, this is KidBotanical, hoping you and your plants thrive.


  1. i've had similar problems as listed above on my indoor growing box.
    My leaves were getting yellow as a result of the fact they got too much water.
    i never realized it destroyed them.
    anyways thanks for those real good tips, really useful!
    +1 and following.

  2. This is chalked full of great tips.

  3. Those arnt hormones buddy, lol... superthrive is potent and rich full of vitamin b1.. An foxfarm is some really good beginners micro nutrients an base nutes... just so you know what's what buddy!