Today we're going to talk about when to start using fertilizers with cannabis; depending on the phase your plant is in it will need certain nutrients. WHAT IS IT? Weed seeds = Elevator Screenings are what is left when grain is run through a seed cleaner. Clean grain goes into a bin and residues = screenings are disposed. Most grain elevators give weed seeds away free to any farmer willing to haul them. Some elevators charge nominal sums for screenings because… Assume there is virtually no nutrition in your potting mix unless it contains compost or coconut fiber.
When to Start Using Fertilizers with Cannabis
In this article we’re going to talk about when to start using fertilizers with cannabis. People always ask us when they should start using fertilizers on their plants, but honestly it depends on your grow method, the strain and the phase that the plant is in.
Depending on the phase your grow is in your plants are going to need certain nutrients in higher proportions; they need more Nitrogen in growth, and phosphorus and potassium for the flowering period. Cannabis plants absorb large quantities of these nutrients as well as others, so if they don’t get them through irrigation then they’ll probably end up showing deficiencies through stains on the leaves.
To start using nitrogen during the growth phase you’ll need to wait for your little plant to grow the roots out enough so that it becomes slightly stronger. It won’t need much more than some humidity to germinate and grow during the first few days, but once it begins growing aster then you’ll need to start using a growth fertilizer.
You should begin off with small dosages; if your product says 4ml/L for adult plants then you need to start off with 1ml/L, and only begin using it once the leaves on your plant have three points. Once those leaves appear you can start using your growth fertilizer in the irrigation water. Once the plant begins growing more then you should raise the dosage until you reach the maximum milliliters allowed, and always use it with every second watering.
For the rest of the grow, regardless of what products you use, you will need to use them on every second watering or else you’ll burn out the roots. If you notice the plant getting yellow then you can use fertilizers twice in a row, but if it gets a dense dark green color then you’ll need to lay off on the fertilizers for a couple of waterings.
Once the female flowers begin showing then you’ll need to begin using flowering fertilizers. Just like in the growth period, you’ll need to start off little by little until you reach the maximum milliliters stated by the fertilizer manufacturer, alternating between pure water and fertilizers.
Each brand has a different range of products, so depending on the brand you go with you’ll need to use more or less products for both growth and flowering, although in this article we’re just talking about WHEN to use them.
If you buy a product with root stimulants in it then you should use it during the first two growth weeks and for two weeks after every time you transplant. If you have a flowering stimulant then you’ll need to use it once you flip the lights to 12 until the first flowers start appearing.
If your chosen range of liquids has a fattener with a high PK you’ll need to use it during the last phase of the flowering period, the fattening period.
Author: Javier Chinesta
Translation: Ciara Murphy
WEED SEED MEAL FERTILIZER
WHAT IS IT? Weed seeds = Elevator Screenings are what is left when grain is run through a seed cleaner. Clean grain goes into a bin and residues = screenings are disposed. Most grain elevators give weed seeds away free to any farmer willing to haul them. Some elevators charge nominal sums for screenings because they can be fed to animals. For example, 10% to 15% weed seeds can be mixed into chicken feed.
HOW TO MAKE WEED SEED MEAL: Seeds of most plants make good fertilizer. The trick is to mill = grind seeds into a coarse meal or flour so they do not sprout. Most farmers use roller mills, hammer mills, or gristmills to grind weed seeds. If milling equipment is not available weed seeds can be baked in shallow (2 inch ~ 5 centimeter deep) pans at 350 degrees Fahrenheit ~ 176 degrees Centigrade for 1 hour to kill seeds. Baked weed seeds make very slow release organic fertilizer ideal for plants (like roses) sensitive to excess nitrogen.
If weed seeds are not available, substitute any type of waste or spoiled grain, for example, wet or dry brewer’s grains. There is no standard analysis for weed seed meal; nutrient content varies depending on species and proportion which change by locality and season. It is good practice to test weed seed samples yearly so fertilizer application rates can be adjusted as needed.
Below are some average nitrogen (N), phosphorous (P), and potassium (K) values for rough calculations. Note: lb = pound. 1 pound = 0.454 kilogram. 1 American ton = 2,000 pounds = 908 kilograms = 0.908 metric ton. 1 metric ton = 1 megagram = 1,000,000 grams = 1,000 kilograms = 2,200 pounds = 1.1 American tons.
WEED SEED MEAL & SIMILAR AGRICULTURAL WASTES. FERTILIZER ANALYSIS IN PERCENT BY WEIGHT (Nitrogen : Phosphorous: Potassium):
BARLEY (spoiled, dry): 1.75% N : 0.75% P : 0.50% K = 35 lb N + 15 lb P + 10 lb K per ton (Manitoba 2011)
BEANS, SOUP (broken, dry): 4.0% N : 1.20% P : 1.30% K = 80 lb N + 24 lb P + 26 lb K per ton (New York 1988)
BREWER’S GRAINS (dry): 4.53% N : 0.47% P : 0.24% K = 90 lb N + 9 lb P + 4 lb K per ton (Pennsylvania 2012)
BREWER’S GRAINS (wet): 0.90% N : 0.50% P : 0.05% K = 18 lb N + 10 lb P + 1 lb K per ton (Pennsylvania 2012)
CANOLA SEED MEAL: 6% N : 2% P : 1% K = 120 lb N + 40 lb P + 20 lb K per ton (Saskatchewan 2014)
CASTOR BEANS (pressed): 5.5% N : 2.25 % P : 1.125% K = 110 lb N + 45 lb P + 22 lb K per ton (Egypt 2012)
COFFEE GROUNDS (dry): 2.0% N : 0.35% P : 0.52% K = 40 lb N + 7 lb P + 10 lb K per ton (Uganda 2015)
CORN, DENT (spoiled, dry): 1.65% N : 0.65% P : 0.40% K = 33 lb N + 13 lb P + 8 lb K per ton (Maryland 2014)
COTTON SEED (whole): 3.15% N : 1.25% P : 1.15% K = 63 lb N + 25 lb P + 23 lb K per ton (USDA 2015)
COTTON SEED (pressed): 4.51% N : 0.64% P : 1.25% K = 90 lb N + 12 lb P + 25 lb K per ton (USDA 2015)
COTTON SEED MEAL: 6.6% N: 1.67% P : 1.55% K = 132 lb N + 33 lb P + 31 lb K per ton (Egypt 2012)
COWPEAS (broken, dry): 3.10% N : 1.00% P : 1.20% K = 62 lb N + 20 lb P + 24 lb K per ton (California 2014)
FLAXSEED = LINSEED MEAL: 5.66% N : 0.87% P : 1.24% K = 113 lb N + 17 lb P + 24 lb K per ton (Manitoba 2008)
OATS (broken, dry): 2.00% N : 0.80% P : 0.60% K = 40 lb N + 16 lb P + 12 lb K per ton (New York 2010)
RICE BRAN: 4.00% N : 3.00% P : 1.00% K = 80 lb N + 60 lb P : 20 lb K per ton (India 2015)
RICE, BROWN (spoiled, dry): 1.0% N : 0.48% P : 0.32% K = 20 lb N + 9 lb P + 6 lb K per ton (California 2016)
RICE HULLS = HUSKS: 1.9% N : 0.48% P : 0.81% K = 38 lb N + 9 lb P + 16 lb K per ton (Philippines 2014)
RICE, WHITE (broken): 1% N : 0.21% P : 0.27% K = 20 lb N + 4 lb P + 5 lb K per ton (California 2016)
SOYBEAN MEAL: 7.0% N : 2.0% P : 0.0% K = 140 lb N + 40 lb P + 0 lb K per ton (Brazil 2011)
WEED SEED MEAL: 2.7% N : 0.90 % P : 0.90% K = 54 lb N + 18 lb P + 18 lb K per ton (Hungary 2013)
WEED SEED MEAL: 3.02% N : 0.56% P : 0.77% K = 60 lb N + 11 lb P + 15 lb K per ton (Saskatchewan 2015)
WHEAT, HARD RED WINTER (broken): 2.00% N : 0.85% P :0.50% K = 40 lb N + 17 lb P + 10 lb K per ton (Kansas 2011)
For comparison, fresh dairy cow manure (86% water) contains 0.60% Nitrogen : 0.15% Phosphorous : 0.45% Potassium = 12 lb N + 3 lb P + 9 lb K per ton. Cow manure is the traditional standard against which all other organic fertilizers are measured.
For slow release fertilizer mill weed seeds into coarse flakes or meal. Grind weed seeds into powder for fast acting fertilizer.
WEED SEED MEAL APPLICATION RATES: Calculate application rates according to soil test recommendation for desired crop. Minimum application rate is 1 ton = 2,000 pounds per acre ~ 5 pounds or 1 gallon per 100 square feet ~ 2 Tablespoons or 2/3 ounce per square foot. Apply 1 pound of weed seed meal for every 25 feet of row or trench. Mix 1/2 to 1 cup of weed seed meal in each bushel (8 gallons) of potting soil.
Average density of weed seed meal = 0.3125 to 0.40 ounce per Tablespoon ~ 5 to 6.5 ounces per cup ~ 20 to 25.6 ounces per quart ~ 80 to 102.4 ounces per gallon ~ 5 pounds to 6 pounds 6.4 ounces per gallon ~ 40 to 51 pounds per bushel (8 gallons). 1 ton = 2,000 pounds weed seed meal = 40 to 50 bushels.
For example: 200 bushel per acre corn crop requires 200 pounds of nitrogen per acre. 200 pounds N divided by 54 pounds of nitrogen per ton of weed seed meal = 3.70 ~ 4 tons of weed seed meal needed per acre of corn. Weed seed meal can be tilled into the earth by conventional plowing, broadcast on soil surface, side banded down rows, or drilled into furrows or trenches.
For feeding earthworms broadcast weed seed meal (1 ton per acre or 2 Tablespoons per square foot) on soil surface. Reapply throughout the growing season when meal is no longer visible.
–> Weed seed meal is a natural = biological = organic fertilizer that requires decomposition before nutrients are available to plants. Bacteria, fungi and many other soil organisms eat weed seed meal then excrete nutrients in plant available forms. As soil organisms live and die, nutrients are constantly recycled = most fertilizer is tied up in the bodies of soil “critters” and is only available to plant roots in small amounts over extended time periods. Thus, weed seed meal is a slow release fertilizer that will not burn plant roots or leach from the soil.
–> Cold, wet soils delay weed seed meal decomposition. Warm, moist soils speed fertilizer availability. Early season crops may show signs of nitrogen deficiency (light green leaves) if soils are especially cold or poorly aerated = oxygen deficient. This is a temporary condition that will ordinarily correct itself in 2 or 3 weeks. Every 5 degree Fahrenheit temperature increase doubles microbial activity. As soils warm, nutrient cycling speeds up and more fertilizer is released for absorption by plant roots.
–> If crops must be seeded in cold soils, apply weed seed meal 2 to 3 weeks before planting so soil organisms have more time to decompose fertilizer and make nutrients available to plants.
–> Weed seed meal is an indirect fertilizer — it feeds soil organisms rather than plant roots. Large amounts of weed seed meal can be applied without crop damage or nutrient loss because the fertilizer is held by soil biology rather than soil chemistry. Thus, nutrients can be banked = stored for use by following crops. Weed seed meal has a “half-life” of several years. Nutrients are continually released in small amounts long after fertilizer is applied.
–> Weed seed meal works best on soils managed biologically. Chemically managed soils typically have smaller populations of soil organisms. Fewer “critters” slows nutrient cycling and restricts fertilizer absorption by plant roots.
–> To use LIVE weed seeds as fertilizer broadcast seeds into a standing cover crop like Red Clover (Trifolium pratense). Earthworms, ants, beetles and other critters eat the weed seeds. Clover kills any weeds that germinate. Caution: Do not try this unless you have a tall, aggressive cover crop that blankets the soil with dense shade.
RELATED PUBLICATIONS: Crop Rotation Primer; Biblical Agronomy; The Twelve Apostles; Managing Weeds as Cover Crops; Trash Farming; No-Till Hungarian Stock Squash; Planting Maize with Living Mulches; Living Mulches for Weed Control; Organic Herbicides; Pelleted Seed Primer; Crops Among the Weeds; Forage Maize for Soil Improvement; Forage Radish Primer; and Rototiller Primer.
WOULD YOU LIKE TO KNOW MORE? Contact the Author directly if you have any questions or need additional information on fertilizing soils with weed seed meal.
Please visit: http://www.worldagriculturesolutions.com — or — send your questions to: Eric Koperek, Editor, World Agriculture Solutions, 413 Cedar Drive, Moon Township, Pennsylvania, 15108 United States of America — or — send an e-mail to: Eric Koperek = [email protected]
ABOUT THE AUTHOR: Mr. Koperek is a plant breeder who farms in Pennsylvania during summer and Florida over winter. (Growing 2 generations yearly speeds development of new crop varieties).
Cannabis Fertilization Requirements at Each Stage of Growth
Assume there is virtually no nutrition in your potting mix unless it contains compost or coconut fiber.
While your specific growing situation and especially your varieties will likely lead to adjustments in fertility inputs, these general guidelines have produced many successful cannabis crops.
1. Seedling or Cutting
The plant can live for a time off of nutrients in the seed. Use minimal or no fertilizer in the early seedling stage. Rooted cuttings are often deficient after propagation. Feed both very gently with a 1-1-1 balanced formula at about 100 ppm for each once there is adequate root development.
2. Vegetative Growth
The vegetative growth stage averages 4 weeks, but can be as short as 2 weeks or as long as 2 months depending on environment, variety and container size. After transplant, kick feed rates up to about 200 ppm N, 120 ppm P2O5 and 200-250 ppm K2O for vegetative growth.
3. Early Bloom
Extra calcium and magnesium are important additions at the start of the bloom stage to produce strong sturdy plants with heavy buds and a robust root system. Shift to roughly 200-250 ppm N-P2O5-K2O at the start of bloom. There should be a little boron in the feed program by the start of blooming. Definitely apply more potash than nitrogen during all bloom stages. Reduce nitrogen somewhat more if plants are large.
4. Late Bloom
At week 5 of bloom, reduce N applications to about 125 ppm, and make sure you have adequate phosphorus once the calyx or sepals form. Use about a 1 to 1.5 ratio of N to K2O in the last four weeks of bloom. Potassium silicate may help strengthen plants during the latter part of the blooming cycle.
At bloom week 9, most growers flush with clear water with no added fertilization. Use some calcium nitrate and kelp extracts if possible throughout the crop.
You’ll want to monitor pH and EC, at least weekly. It’s a good idea to run a leaf analysis at an in-state lab at about bloom set, but check with your lab about the legalities involved. Throughout production you water with only clear water once every 10-14 days, depending on EC readings.
Assume there is virtually no nutrition in your potting mix unless it contains compost or coconut fiber.