Raised garden beds can benefit greatly from cover crops, not only these cover crops will stop erosion but they will also feed the soil for the next crop. No matter how small or large your raised garden beds are you should still grow cover crops during the off-season. The soil needs plants in order to thrive, without cover crops or some kind of mulch the topsoil will slowly be eroded, thus lowering its fertility significantly.
Ideally, you should grow cover crops in your raised garden beds which benefit the following crops. For example, if you are going to grow vegetables that need a lot of nitrogen then you should use nitrogen fixer cover crops. In addition to this, you should also take into consideration the size of your garden beds, the smaller the raised garden bed is the smaller the cover crop should be, for smaller garden beds you should use Clover while for larger ones you should use Rye and Oats.
If your raised garden bed has garden fabric on the bottom to stop weeds from sprouting then you should use smaller cover crops like clover, mustard, and buckwheat as these will not damage the underlying garden fabric. The roots of most cover crops are not strong enough to pierce through the garden fabric, but if the cover crops are in large numbers then their combined pressure from the roots can damage the garden fabric. If you want to know how to fill a raised garden bed for cheap then check out my recent article How To Fill A Raised Garden Bed Cheap ( Top 13 Ways ).
Cover Crops For Raised Beds
Cover crops are a valuable tool for improving soil health, suppressing weeds, and preventing erosion. When my raised beds are not in use, I sow cover crop seeds such as clover, rye, or buckwheat to provide a protective cover over the soil. These cover crops help to retain moisture, prevent weed growth, and add organic matter to the soil when they are eventually turned under. The cover crops also attract beneficial insects and help break up compacted soil. Before planting my main crops, I simply cut down the cover crops and incorporate them into the soil, allowing them to decompose and enrich the bed.
Crimson Clover
Crimson clover is probably the best cover crop for raised garden beds, it grows relatively fast, is excellent at suppressing weeds, and also fixes nitrogen into the soil. As this is a relatively small-sized cover crop, you can easily use it even in the smallest raised garden beds with amazing results. Crimson clover can be planted in the fall or spring and turned in the fall or spring.
Fava Beans
Fava beans are extremely good at fixing nitrogen, and the main reason why they are extremely good for raised garden beds is due to their shallow roots and relatively large biomass. In addition to this fava beans tend to thrive in colder climates and will also grow well if the soil has poor drainage. Fava beans have to be planted either in the early spring or late summer and turned in early summer or fall. If you want to know how to amend clay soil without tilling then check out my recent article How To Amend Clay Soil Without Tilling ( Top 8 Methods ).
Rye
Rye is one of the most common cover crops used by farmers, although it doesn’t necessarily mean that you need to have a big plot of land in order to benefit from rye as a cover crop. Rye is also an excellent cover crop for raised garden beds, it tends to grow relatively fast and if you have done a good job at sowing then they will be excellent at suppressing weeds. Rye has to be sown in the fall, and you have to turn it during the spring.
Oats
Oats are an excellent cover crop for raised beds, although it not as winter hardy as some other cover crops like winter rye for example. Even though it is not as winter hardy as some other cover crops you can still let it die back naturally. The main benefit of using oats as a cover crop for your raised garden beds comes from their root structure, as they can pierce the ground to around 30-40 inches. You can plant oats during the spring or fall, and you can turn them during the spring or summer. If you want to know how to get rid of slugs then check out my recent article How To Get Rid Of Slugs And Snails ( Top 19 Methods ).
Hairy Vetch
Hairy vetch is a nitrogen-fixing legume, which means that it is able to absorb nitrogen from the air with the help of beneficial bacteria. Once you cut or till this cover crop the excess nitrogen will be available for the next crop. The main reason why this is an excellent cover crop for raised garden beds is due to how fast it grows. Hairy Vetch has to be planted during the fall and turned in the spring. Just keep in mind that most of the growth will happen during the spring.
Buckwheat
If you have a problem with weeds in your raised garden beds then you should definitely grow buckwheat. Buckwheat tends to outcompete most weeds, and in a matter of weeks, it will suppress most weeds. Make sure to cut the buckwheat before it produces seeds, or else you might have a serious buckwheat problem if you live in a fairly mild climate. Buckwheat can be planted both during the fall or spring, and you have to turn it during the spring or fall.
Garden Peas
Garden peas have been used for a very long time as a cover crop, and they are especially good for smaller gardens like gardens with raised beds. Garden peas are good nitrogen fixer cover crops and they also tend to grow relatively fast. Garden peas have to be planted in the fall and have to be turned in the spring.
Cowpea
Cowpea is a nitrogen fixer plant, which means that it absorbs nitrogen from the air with the help of bacteria, once you cut the cowpea this excess nitrogen will be available for the next crop. A lot of people actually till the cut cowpeas into the soil, although you can also use it as a mulch once you cut it down. Cowpeas have to be planted during the summer and turned or cut down during the early spring.
Barley
Barley is an excellent fall season cover crop, especially if you have excess salts in the soil due to chemical fertilizers. Barley tends to grow relatively fast and once they are turned they will act as a mulch, suppressing weeds and feeding the soil at the same time. Barley can be planted during the fall or spring, although if the local winter is mild enough then fall planting is definitely the better option.
Alfalfa
Alfalfa is a type of legume that is excellent at breaking down the soil, this cover crop is especially good if your soil is mostly clay. Just keep in mind that alfalfa will not grow in compacted clay soil, so make sure to till the soil or use some kind of organic mulch. The best part about using alfalfa as a cover crop is that it can be planted from spring up to late summer. The turning time for alfalfa is during the spring or fall.
Winter
Winter wheat is an extremely good cover crop for raised garden beds due to a large amount of organic material it provides the soil with once it is tilled or turned into the soil. Winter wheat is also good at suppressing weeds, and oftentimes it will simply out-compete them. Winter wheat is planted in the fall and tilled or turned during the spring.
Key Takeaways
- Choose cover crops that are well-suited for your specific raised bed conditions and goals. Consider factors such as the time of year, desired benefits (e.g., soil fertility, weed suppression, erosion control), and the duration of cover crop growth.
- Timing is crucial when it comes to planting cover crops. Ideally, sow the seeds after harvesting your main crop or during fallow periods. Follow the recommended planting times for each specific cover crop to maximize their benefits.
- Once the cover crops have grown to the desired stage, cut them down and incorporate the plant material into the soil. This can be done by mowing or using a garden fork to chop and mix the cover crop residues into the top layer of the soil. This process adds organic matter, improves soil structure, and releases nutrients as the cover crop decomposes.