Alfalfa cowl crop: Helpful nitrogen topper

You have probably struggled with the soil in at least one of your beds. You may have tried paving fancy garden soil mixes or tried to loosen the soil by manual plowing with no result. One way to improve the soil in a garden bed is to introduce an alfalfa catch crop.

There are so many benefits to sowing an annual cover crop in a garden. With the foresight to include this practice in your annual garden plan, you can be an excellent preparation for the upcoming growing season, especially since you start with a substantial and enriched soil structure.

So what is alfalfa anyway? And what is this concept of covering? And why should we choose alfalfa as a catch crop instead of others? Feel free to read on to find out! Perhaps your next seed purchase for planting will be a winter catch crop.

What are cover crops?

An alfalfa cover crop is a great addition to your annual winter prep. Source: ag.inspire

First, let's talk about growing catch crops. The seeds are sown to cover the soil and the organic material produced will eventually improve the overall structure of the soil and the conditions of the molecular structure of the soil. By adding all of these beneficial organics to the soil, you are also improving the soil's moisture holding capacity. At the same time, you prevent excessive weed spreading by choosing what should grow in this space. It's a win-win to get used to your garden area!

Some elements of cover crop growing also come from companion planting techniques. A cover crop can be grown between rows of other plants to loosen the soil and prepare it for later sowing. This will reduce weed spread, but also ensure that you can work these areas between rows later if desired.

This process supports the stability of future yields and feeds the land in a synergy that cannot be achieved anywhere else. Today catch crop seeds are planted in an area that needs improvement or protection from erosion or weed development.

Types of cover crops

There are 4 different types of covers to consider. Everyone has their proper use and function. Take these into account before you start planting.


First, there are grasses that are great for planting when you want to catch leftover food from an earlier harvest. We are talking about wheat, ryegrass and barley. If you chop them to the ground and work them in, the high carbon content in the plant will remain while the nitrogen is released into the soil. All catch crops require a period of degradation before the nutrients are available to the plant.


There are legumes that are planted to fix nitrogen in the soil, which may be a better choice if you want a garden that guarantees vigorous root growth. Legumes such as clover and vetch degrade faster than grasses and help protect against erosion. Often times, people plant legumes with grasses to serve a dual purpose in their greening practice.


Brassicas are a great catch crop to eat. They produce a lot of good biomass that will help prevent garden soil in the fall. They also contain molecular compounds that are great for pest control. But they are often planted under other catch crops because, while beneficial, they are not as strong as others.

When you grow a brassica root vegetable like radishes, they also loosen the soil.

Deciduous plants

Non-legume broadleaf plants are similar to cabbage plants in that they grow quickly in the fall and add good biomass to your garden soil. Spinach is a great choice for fall as it will survive winter too. They can absorb nutrients from last season's harvest.

So what exactly does a catch crop do to help new plants that will exist there in the future?

Benefits of cover cropping

LuzernefeldIn commercial agriculture, alfalfa covers are plowed into the ground to improve it. Source: USDAgov

Here is a list of the benefits a catch crop can bring to a garden or farm.

  • They prevent soil erosion. By sowing cereals and grasses, you have a firmer soil structure that can withstand rain and retain its structure more easily.
  • They control soil fertility. By plowing in a stray crop before it can be sown, you are giving your garden a great source of green manure that is slow to break down. The plant residues fertilize the soil over a long period of time and provide nutrients in the long term. The roots also loosen and aerate the soil.
  • They will help you maintain soil health over time. When the crops are degraded, the fertility of the soil continues to improve. This is not only about a higher nitrogen-fixing content, but also about better relationships with mycorrhizal fungi, which are necessary for healthy soil.
  • They manage the water drainage. This relates directly to the piece of soil erosion discussed above. Since the soil is more structurally stable, it and the roots of the plants can store and absorb more moisture, which prevents the soil from draining. Retained moisture also means you have to water a lot less.
  • They keep weeds out. Because they are dense, there is no place for weeds. This also means fewer weeds will advance in your garden.
  • They reduce the spread of diseases. Diseases can come from a poor soil source, insects, or from neighboring gardens and farms. Some covers suppress disease cycles and can be particularly effective against fungal diseases. Many of these plants contain elements that are also poisonous to certain fungi and nematodes.
  • They fight pests. You can grow covers as trap cultures to keep pesky insects away from other parts of your garden. Some catch crops also attract beneficial insects.
  • They benefit from wildlife. Catch crops attract birds, bees, and other animals that can aid pollination in your garden. That way, you can also be a wildlife steward of the land. Higher pollination rates and higher bird rates in a garden mean fewer pests, better production, and higher yields.

What is alfalfa

Alfalfa (Medicago sativa) is a perennial plant in the pea family. Also called alfalfa, it is used worldwide as a fodder crop. People grow alfalfa to feed livestock or use as green manure. It's a popular animal feed, and when dried and ground it's a nitrogen-rich fertilizer. It can even be chopped and dropped on the surface and treated like straw mulch.

It has a long history from Iran, its country of origin, to your sandwich. You may already know that alfalfa sprouts are widely used in food today.

People tend to grow alfalfa plants as an annual catch crop because growing alfalfa brings several benefits to the garden. Medicago sativa provides organic material that has been proven time and time again to improve soil health.

Planting alfalfa is also easy and straightforward. Even better, this perennial is a good source of food for humans and animals. Alfalfa sprouts are high in protein. If farmers choose to grow an alfalfa sprout into seedlings, they can use it to feed their cattle the resulting hay instead of buying wheat straw or alfalfa hay bales from a feed store.

Benefits of an alfalfa cover plant

Alfalfa hayAlfalfa is popular both as a cattle feed and as a soil improver. Source: Cowgirl Jules

An alfalfa crop offers a combination of what all types of covers do. Lucerne plants have long side roots that penetrate and loosen the soil.

Put alfalfa in garden soil where you want to fix nitrogen and have some green manure to keep this cycle going.

Medicago sativa improves soil structure, holds water and suppresses weeds. Useful predatory insects love alfalfa and will help get rid of any pests that live nearby.

Pollinators also appreciate it when gardeners grow alfalfa, because as alfalfa blossoms, leaf cutter bees move into the openly pollinated area to fetch nectar. Other bees love alfalfa too, as do a host of other pollinating insects.

The flowers are beautiful, and if you prune alfalfa back in time, you have a great source of food for the future. If you don't work in alfalfa, no problem. It's also a great source of mulch.

Disadvantages of an alfalfa cover plant

There are only a few things to consider with alfalfa. Let's talk about two important points.

Timed coordination

The first thing to consider with alfalfa is timing. In locations that get very cold in winter, avoid planting in the late autumn months. You will need to start your sowing earlier to ensure germination and adequate development of established plants for the area to be covered.

Planting alfalfa seeds early is best for those in colder regions. Planting in late fall is best for those in warmer regions to allow seedlings to be established and to survive (or at least cover) the soil through the winter. While it's okay for the plants to die off over the winter months as it will only speed up their decomposition, you still want to have enough cover to prevent weeds from spreading before they do.


The other problem that occurs with crops like wheat, alfalfa, and other perennial crops that are used for soil construction is that if not harvested at the right time, they become ready for sowing. If not cut at the right time of harvest, the seeds will go through the process of spreading and germination, and the seedlings will grow long lateral roots into the ground. This, too, can deplete the soil prematurely.

To prevent this germination, cut up the alfalfa and either harvest it or use it as a mulch before it is used for sowing. We will go into the details of the harvest in the next section.

How to plant an alfalfa cover crop

Vigorously growing alfalfaThe luscious green foliage of the alfalfa is pretty pretty. Source: Herbolario Allium

Let's discuss a few growing tips for planting alfalfa. Whether you're trying to loosen the soil, grow it as feed, or feed cattle, this should include the basics Lucerne breeders need to know.

Growing demands

Alfalfa likes full sun and soil that does not contain too much moisture. Because the roots are used to drought-prone areas, you don't need to add organics such as mulch to the seeds to trap moisture.

Planting alfalfa in an area that doesn't drain well or gets drenched will cause rot. Also choose neutral ground.

When to plant seeds

Plant alfalfa seeds according to your region. Make sure there is enough cool weather to keep alfalfa happy, but warm enough for it to establish itself.

In zones where winter is long and cold, start sowing alfalfa seeds in spring. This allows the seedlings to establish themselves in the temperate spring and summer months. Harvest in autumn.

If you are in a mild region, plant seeds in the fall and let them survive the mild winter, then harvest in the spring.

Ways to Target Your Harvest

There are several ways to plant this perennial legume in your garden. You can simply spread seeds over a large area in spring or autumn.

This can be in a raised bed, row, or large area that you want to prepare for gardening, foraging, or farming.

You can also harvest the seeds in spring or autumn by throwing rows of alfalfa between other crops. This is a great way to make sure you have food and nutrition, and can also be a great way to trap pests as a catch crop.

Rowing cover crops is a great way to upgrade alternating rows of soil for the next season. Remember to keep the rows of seeds at least 18 to 24 inches apart.

How to Plant Seeds

If you are into large scale farming or farming, you need a lot of seeds. The general rule for a perennial plant like alfalfa is around 12 to 15 pounds of seeds per acre. This is the optimal yield.

Most of the home gardens are on approximately a quarter of an acre lot. So adjust your seed rate to the area in which you are growing. Sometimes home gardens are only a small part of that quarter of acres. So you may only need a few pounds of seeds.

To plant seeds, send enough for the planting area. No tamping or covering with organic material required. The seeds germinate on the ground within two weeks. If you have a lot of birds or wildlife that will consume your emitted seeds before they sprout, you can spread a thin layer of soil over the surface or loosely rake in the seeds, but this is not strictly necessary.


Once the seed germinates, all you have to do is pick it up and wait for the timing to be right.

When feeding animals, let the perennial get to the point where it is about to bloom. This is when the diet is at its highest. Then cut it off and heal it. After hardening, it is suitable as a feed.

If you are using the perennial to fertilize your soil, let it bloom and before you sow, dig it down and into the ground. Then let that goodness release into the ground for your next harvest.

For people making raised bed ceilings, it is often easiest to use a chop-and-drop method. Wait for the alfalfa to start blooming, then cut it back and leave the cut material right in the bed. Soil cultivation is not absolutely necessary! By the spring planting time, you will have nutrient-rich soil ready to go.

frequently asked Questions

Alfalfa ready to re-sow itselfCut back alfalfa before it sets seeds to prevent natural overseeding. Source: eggrol

Q: is alfalfa a nitrogen fixer?

A: Indeed! That's one of the things it's most used for.

Q: What is the fastest growing cover crop?

A: Buckwheat grows the fastest, around 4 weeks from seed to flower.

Q: What is the best cover crop for nitrogen?

A: Each legume feeds the soil with nitrogen and fixes it very well. Alfalfa is certainly one of the most popular!

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