Of all the farmers I’ve talked to about cover crops, the number who are using them with vegetable crops is a minority. But as a vegetable farmer myself, I’ll be the first to say that cover crops can do great things for your veggie crops.
Just like any other application, it takes some preparation, and each crop has its own needs and challenges.
Here are some tips for using cover crops with vegetables:
Know the limitations
Cover crops are a tool, and they come with great benefits and some limitations.
For example, they’re not always best for influencing early production. If you have a roadside stand or sell to a local store, having the first tomatoes in the neighborhood is a magnet for customers and sets you up for season-long buyers.
Compared to raised beds and plastic, the cooler soil may mean that your earliest harvesting opportunities are delayed. This can be rectified by using high tunnels, which is what I’ve successfully done to overcome this limitation.
Cover crops also take more management than just doing whatever you’ve been doing. There’s a learning curve, and you need to spend some time and effort honing your knowledge!
Experience the benefits
On the other hand, there are great advantages to using cover crops. I’ve used them for over 20 years to grow cleaner pumpkins and squash — a result of the fruit growing on the roller-crimped mulch.
For early planted sweet corn, cover crop radishes seeded in the fall will provide an ideal seedbed to plant into. Contrary to the cooler conditions outlined above, the holes left by the decayed radishes allow for the soil to warm up quicker and can enhance the harvest date of this crop. In addition, growing hairy vetch for late-planted sweet corn can all but eliminate nitrogen needs.
Think about your intended crop
Depending on what you’re hoping to plant, you’ll want to tailor your cover crop strategy to best match the vegetable crop you have in mind. Planting dates, seeding rates and cover crop species in the mix you use will all be slightly different from crop to crop.
Think about what you want to accomplish. If it’s primarily weed control, then plant the cover crop thicker so the weeds will be suppressed. For nitrogen production, lean heavily on legumes. For pumpkins, having cereal rye or triticale in the mix gives that much-needed mulch to keep them clean.
There is no one-size-fits-all approach to cover cropping.
Sweet corn is typically planted over a three-month time frame. In addition to the other recommendations, I suggest a multispecies mix for the middle plantings.
The needs of each vegetable crop and its accompanying cover crop vary depending on time of year, and the relationship between them is crucial!
Cover crops that are fully headed out or flowering may be killed using a roller crimper, but younger cover crops will need the addition of a burndown herbicide. While shorter cover crops are better than nothing, try to maximize growth to receive all the benefits they have to offer.
Consider your planting method
Is your vegetable crop going to be direct-seeded or transplant? I’ve done both successfully, but each takes specific planning and equipment.
With transplanting, there’s not much equipment out there made specifically for transplanting tomatoes and the like into cover crops. You may have to get creative and modify conventional transplanters.
Some have strip tilled to use existing machinery without any modifications. No-till corn planters can be used to direct-seed pumpkins and squash, but seed spacing may be erratic.
Serious growers will invest in the correct seed meters or seed disks that can accommodate irregularly shaped vegetable seeds.
The coach’s closer
Vegetable farmers can indeed enjoy the benefits of cover crops, too! With some thought and creative management, you can plan this season to get your fields ready for cover crop and no-till success next year.
Groff is a cover crop pioneer and innovator who farms in the Chesapeake Bay Watershed. Check out his website, covercropcoaching.com.