Seed Weed Fertilizer

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. Seaweed Fertilizer (Seaweed Extract): Learn how and when to use seaweed fertilizer in your garden for the many health benefits it provides. [GUIDE] 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…

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

Seaweed Fertilizer: When To Use Seaweed Extract In Your Garden

Seaweed fertilizer is essentially plant food just like bonemeal fertilizer.

Fertilizers made from seaweed are a great source of nutrients and trace elements (absorbed from the sea) for plants grown in containers or even those grown on the ground.

They’re eco-friendly and sustainable and contain micronutrients to enrich your soil and increase crop yields.

You may find it by different names such as bladderwrack or kelp.

Although most seaweed fertilizer is marine kelp, freshwater seaweed is also rich in minerals like nitrogen, and phosphorus and may be used to supply nutrients to your plants.

What Is Seaweed Fertilizer?

Seaweed may be used whole, as a liquid or it may be composted and crushed before it is added to the soil as fertilizer.

See also  Fast Growing Weed Seeds

There are different types of seaweed fertilizers generally made of kelp extract and found in varying forms such as:

  • Liquid Seaweed Fertilizer– best for plants grown in containers since it soaks through easily and plants get nutrients faster.
  • Seaweed Extract Powder– this is a very potent fertilizer and is obtained by drying out all the water from seaweed.
  • It is extracted from brown seaweed such as Ascophyllum Nodosum, Laminaria, etc.
  • Seaweed/ Kelp Meal– this is essentially dried and crushed seaweed.
  • Calcified Seaweed– this one isn’t kelp fertilizer.
  • It is a mix of calcified coral and algae (with around a 50% calcium content).

There are many different brands of seaweed fertilizer with Neptune’s Harvest (Amazon) being one of the more popular options.

Their liquid fertilizer ingredients have an indefinite shelf life since they are only activated once the water is added to them.

How Do You Use Seaweed Fertilizer in The Garden?

Seaweed fertilizers help improve your plants’ health.

They may be applied to the soil as mulch or mixed in with the compost pile.

Avoid rinsing the seaweed beforehand to remove the salt as this will take away many of its positive micronutrients and alginates.

The salt may get washed out by rainwater or hose down the soil after applying the fertilizer.

Alternatively, seaweed fertilizer can be applied through a foliar method—applying it directly onto the leaves.

Before you begin, check for and remove any dead or decaying leaves.

Use a diluted form of liquid fertilizer (liquid kelp) and spray it in the form of a light mist over the leaves.

You may either use a foliar spray for this or attach the liquid with your hose and fertilize while watering the plants.

Some gardeners may use a combination of seaweed and fish fertilizer to fertilize their house plants -this seaweed and organic fish emulsion (liquid fish) is sprayed in the foliar method.

Seaweed fertilizers can improve root growth and seed germination.

How Much Alfalfa Meal Should I Use?

Organic fertilizers are best for plants.

Many gardeners use a combination of Alfalfa meal and kelp (or seaweed fertilizer npk) to complete the NPK (Nitrogen- Phosphorus- Potassium) content of the soil.

Alfalfa meal is derived from alfalfa grass and is rich in nitrogen and calcium.

Use the following list as a guide for how much Alfalfa meal you need to use:

  • 12 lbs/ 1000 square feet for a light coat (¼ cup per plant)
  • 25 lbs/ 1000 square feet for a regular coat (1/3 cup per plant)
  • 50 lbs/ 1000 square feet for a heavy application (1/2 cup per plant)

What Are the Benefits of Using Seaweed Fertilizer in Your Garden?

Seaweed products are beneficial to your garden vegetables in a number of ways:

  • It contains nutrients such as NPK and magnesium, iron, zinc, and calcium as well as growth hormones encouraging healthy plant growth.
  • It is a form of mulch keeping the soil damp and reduces the amount of water needed.
  • It reduces the frequency with which you need to weed your garden since it doesn’t contain any seeds (possible weeds).
  • It keeps your vegetable garden free of pests such as slugs, worms, and even birds since all these creatures despise the texture and saltiness of fresh seaweed.
  • It helps plants build immunity against fungi and diseases.
  • Unlike dry fertilizers such as compost and other mulches, seaweed doesn’t blow away in the wind.
  • Seaweed fertilizer keeps the soil aerated and healthy.
  • It enriches plants grown in hydroponics by providing them with the nutrients plants generally extract from the soil.

Are There Any Downsides to Using Seaweed Fertilizer?

Since it is an organic fertilizer, seaweed fertilizer doesn’t really have any significant problems.

One of the main issues is its high salt content and this isn’t particularly detrimental to plant health.

As mentioned previously, the salt may wash out with the rain or when you water your garden.

Another minor issue is when it is applied as a mulch, it may break down faster than it can enrich the plant.

Again, this is avoidable by applying it using the foliar method or mixing it in with the compost heap.

Other than this, there aren’t any significant downsides to using seaweed fertilizer.

See also  Composting Weed Seeds


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.


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.

See also  Chronic Weed Seeds

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: — 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).