ALFALFA as Fertilizer and Soil Amendment


You can make your own soil amendment using alfalfa in multiple ways. Work alfalfa into planting beds, layer as an early side dressing for nitrogen-loving plants and brew it into a tea ideal for soil drenches.

How to use alfalfa as fertilizer

What is Alfalfa?

Alfalfa, a nitrogen-rich legume, is used as livestock feed and is also abundant in an array of macro and micronutrients.

Benefits of Alfalfa

Alfalfa encourages microbial activity in the soil, breaks down quickly and stimulates plant growth.

Without enough nitrogen, plants are stunted and foliage will take on a pale yellow tint. Tomatoes with a nitrogen deficiency will get purple-looking veins.

Get Alfalfa

You’re in business if you have stale pellets hanging around from a pet rabbit or can snag a small bucketful of horse feed from a friend. The same goes for alfalfa hay. Sometimes animals decide they don’t want to eat the food put in front of them and so it will just sit there until it can be composted or given away.

I got my hands on a bag of pure alfalfa horse feed in pellet form. If you have access to packaged rabbit food, look at the label to check for additives.

Which plants may benefit from alfalfa?

Alfalfa treatments are especially good for nitrogen-loving plants such as sweet corn, lettuce and other greens, broccoli and cabbage (all Brassicas).

Celery, potatoes and carrots can also benefit from a bit more nitrogen but read the tips coming up to find out when it’s best to apply.

There are several reasons why you should not over-apply alfalfa or any nitrogen-rich material.

  1. Alfalfa produces a lot of heat when it decomposes. It will rob the soil of nitrogen while it breaks down because the microbes that work on it need nitrogen for fuel.
  2. Excess nitrogen can decrease the plants ability to fight off disease and pests (aphids will multiply quickly).
  3. You will get lots of leaves but little in the way of fruit or flowers.
  4. If applied too late in the growing cycle, you run the risk of weaker crops, e.g., cracked cabbage heads, split carrots and poor quality potatoes.

Combine alfalfa with…

Alfalfa works well with kelp for added phosphorus and trace minerals. Simply add 2-3 chopped kelp leaves for every cup of alfalfa.

Sometimes I use 2-3 crushed eggshells per square foot along with an alfalfa treatment.

Go get alfalfa soil amendments recipes now…
Alfalfa Pellets Soil Amendment Recipe

To prepare the garden a few weeks before planting, scatter alfalfa pellets in your planting bed. For a 3 foot by 3 foot area use one cup, or 3.5 cups for the entire raised bed. Work into the top layer of soil and water well. A few weeks later, plant your seed or transplants.

For a smaller area, planting hole or container, add a small handful of alfalfa pellets for every square foot and cover with an inch or two of soil before planting.

You can also use baled alfalfa hay to prepare a planting bed although it will take longer than pellets to decompose. Pull the bale apart, lightly spread it in the planting bed and wait at least a month before planting. Or add a 3 inch layer of alfalfa in the fall and it will decompose during winter. Come spring you won’t have to do much to get the garden prepared for planting!

Alfalfa Pellets to Recondition Container Soil Recipe

If you use containers and the soil has lost its life, dump all the spent stuff in a giant tub with drainage holes. Mix equal amounts of alfalfa, chopped kelp leaves and crushed eggshells. Add a cup of this combo for every square foot of soil and let it sit for a month.

Alfalfa Pellets for Compost Recipe

Alfalfa pellets are an effective compost accelerator. There’s no need to buy commercial starter products to rev up the pile. Alfalfa will increases heat and speed decomposition, especially helpful in cool weather.

Use one cup of pellets for every square foot of compost material.

Make sure you add about a square foot of carbon-rich brown materials for every cup of alfalfa pellets to balance out the nitrogen in the alfalfa: dried leaves, straw or uncoated paper work well. Check out my list of 100 Compost Ingredients for more ideas.

Alfalfa Pellets Top Dressing Recipe

Sprinkle alfalfa pellets on top of your garden bed and water in. Do not over apply because excess nitrogen can harm your plants and make them more susceptible to disease.

I use a small handful (about 1/4 cup) for each square foot or two large handfuls (about a cup) for every 3 square feet, making sure the pellets do not touch the plants.

Timing is Important

For vegetables such as cabbage, carrots and potatoes, time your top dressing so that you do not apply the alfalfa too late in the growth cycle.

~Do not add alfalfa after cabbage heads out or you’ll run the risk that it will grow too quickly, become weak and crack.

~For carrots, apply alfalfa a few weeks into growth only. If you apply a month out or even closer to harvest, the carrots might split.

~Just as with cabbage and carrots, potatoes might get weak and become more prone to damage if subjected to too much nitrogen too late. Stop adding any nitrogen-rich fertilizer 60 days prior to harvest. (This is why bagged soil with time released nitrogen fertilizer is not a good idea for potatoes.)

Alfalfa Fertilizer Tea Recipe

For small applications use a quart jar or any similar-sized container. Add ¼ cup (or a small handful) of alfalfa pellets and let sit for 5-10 minutes. Water one plant with the liquid and keep the solids in the container. Add water again and wait another 5-10 minutes to use once more. Keep doing this until all your plants that need nitrogen are fertilized.

To make a larger batch, add 1 cup of alfalfa pellets to a gallon of water or 5 cups to a 5 gallon container.

For a more complete fertilizer, add the same amount of worm castings and/or kelp to the water. The solids leftover from the tea can be worked into the soil or added to your compost bin.

Alfalfa Tea Using Hay Dust Recipe

Compressed bales of alfalfa when shaken will drop fine particles that you can use to make a tea for your plants. Just open the bale of alfalfa over a tarp and sweep up the powder. Place in a pantyhose or sock and tie the end. Drop in a bucket of water and let sit for a day or two. Water your nitrogen-loving plants as usual with the alfalfa tea.

Foliar Feed Recipe

Spray your liquid fertilizer tea on the leaves early morning or evening. Make sure to get the undersides of leaves because they are more porous.

Alfalfa Quick Tips

  • Rabbit alfalfa pellets are smaller than horse alfalfa pellets and may break down faster in water and the soil.
  • Alfalfa feed may have other ingredients added. Check the label or ask.
  • Do not use alfalfa on plants that are going dormant because it will stimulate growth at the wrong time.
  • When alfalfa hay gets wet it can mold and take on a musty smell. Fresh alfalfa hay smells good, like newly cut grass. You can use it for the garden even if it’s starting to spoil.

Usually alfalfa hay is cut and baled before it goes to seed. Try using it as a mulch much like grass clippings. Let it dry out first and apply thinly so it won’t heat up and rob nitrogen from the soil to decompose. As with the side dressing recipe above for pellets, make sure to have a bit of clearance around the plants to prevent nitrogen burn.