Before growing cover crops, you need to ask yourself some questions:
- What type of crop should I plant?
- When and how should I plant the crop?
- When should the crop be killed or incorporated into the soil?
When you select a cover crop, you should consider the soil conditions, climate, and what you want to accomplish by answering these questions:
- Is the main purpose to add available nitrogen to the soil, or to scavenge nutrients and prevent loss from the system? (Legumes add N; other cover crops take up available soil N.)
- Do you want your cover crop to provide large amounts of organic residue?
- Do you plan to use the cover crop as a surface mulch, or incorporate it into the soil?
- Is erosion control in the late fall and early spring your primary objective?
- Is the soil very acidic and infertile, with low availability of nutrients?
- Does the soil have a compaction problem? (Some species, such as sudan grass, sweet clover, and forage radish, are especially good for alleviating compaction.)
- Is weed suppression your main goal? (Some species establish rapidly and vigorously, while some also chemically inhibit weed seed germination.)
- Which species are best for your climate? (Some species are more winter-hardy than others.)
- Will the climate and water-holding properties of your soil cause a cover crop to use so much water that it harms the following crop?
- Are root diseases or plant-parasitic nematodes problems that you need to address? (Winter [cereal] rye, for example, has been found to suppress a number of nematodes in various cropping systems.)
In most cases, there are multiple objectives and multiple choices for cover crops.