Fertilisers and Nutrients for Cannabis
Nutrients, or fertilisers, in our niche at least, refer to 'food for plants'.
Cannabis plants need a certain quantity and type of food in order to grow to
their best potential. The main nutrients in cannabis nutrients are Nitrogen (N),
Phosphorus (P), and Potassium (K).
In addition to these main nutrients, cannabis plants require a lesser amount of
'secondary' nutrients and trace quantities of other elements.
Secondary nutrients are calcium (Ca), sulphur (S), and magnesium (Mg). Trace
elements are small quantities of boron, chlorine, cobalt, copper, iron,
manganese, molybdenum, and zinc. (Add appropriate symbol :-) )
Cannabis fertilisers are always calculated in the N-P-K format; as above, N is
Nitrogen, P is Phosphorus, K is Potassium. So a nutrient/fertiliser. Soil that
displays an NPK ratio of 20-10-10 plant food contains 20% Nitrogen, 10%
Phosphorus and 10% Potassium. You get the picture? The remaining 60% in this
case is made up of secondary nutrients, trace elements and inert materials.
A good quality nutrient soil/fertiliser with secondary nutrients and trace
elements will get you through all stages of growth. But during the different
stages of growth you can, if suitable, change the nutrient levels to suit
individual strains.
Nutrient Requirements
Babies
Regardless of the nutrient soil/fertiliser you choose, during the first 1-2
weeks of life and the first 1-2 weeks of flowering, use half the amount (or
less) of nutrient solution the manufacturer recommends; i.e. if their packaging
says use 10ml per gallon of water, then use just 5ml per gallon of water for
these first few weeks of the stages. It is essential to not over feed then when
they are young. Most times we ourselves will give them no additives with their
water for the first few weeks.
Veg stage
During seedling/vegetative growth the plants need lots of N (nitrogen). They
also need a fair amount of P (phosphorus) and K (potassium), 20-10-10 in our
scenario or something with these similar ratios of N-P-K, and secondary
nutrients, and trace elements will be good.
Flowering
During flowering the plants need more P (phosphorus) and more K (potassium) than
they did during vegetative growth. They need some N (nitrogen) but not as much
as they did during the veg stage. They still also require their secondary
nutrients and trace elements.
If you used 20-10-10, as in our scenario, for the veg stage then try using
10-20-20 for flowering.
Easy Does It
Do not give your plants extra nutes thinking it will make them grow faster. Too
much will kill your plants. If you under feed, plant growth will be slowed down
but they will stay alive far longer than if you feed them too much. Follow the
mixing instructions on your soil nutrient package, if you aren't sure, err on
the side of caution.
Stop feeding the cannabis plants at least 14 days before harvesting when growing in soil. The
last few times you water the plants, don't add any nutrients at all. Pure water
if perfect. This is so the mentioned elements N, P and K etc can be used up by the plant before harvesting. This will help the cannabis in several ways, a
better taste, healthier and a better burn.
Buying Nutrient Based Soils
Most companies that make these soils specifically for cannabis nowadays offer
their ranges with different nutrient ratio's, aimed at both stages of growth,
the vegetative stage and the flowering stage. So as we often do, simply look for
the two combinations from your choice of company.
Two and three part nutrient solutions, that allow you to custom blend the amount
of the different components, are highly recommended to experienced growers.
Organic nutrients are available and highly recommended, they produce the best
cannabis as far as we are concerned, along with the obvious green benefits but
they can be harder to find, and expensive. We personally always use bio products
if possible.
