Ask a Master Gardener: What cover crops should I use?


crimson clover

Crimson clover and other legumes can be used as cover crop in this area, as they obtain their nitrogen from the air and can provide as much nitrogen for your next crops as fertilizer. Legumes need to be tilled into the soil at peak bloom, but before seed has set. Other examples of legumes good in this area are Austrian field peas, hairy vetch, and annual and winter rye.


Question: I'm always looking for ways to improve my soil, and I hear that cover crops are effective. What type should I use and when should I plant it?

Answer: One of the easiest and most cost-effective ways to improve your soil is to plant cover crops, or green manure as it also is called. Adding green manure helps in feeding fungi and bacteria, building soil structure, choking out weeds, increasing water holding capacity in the soil, and bringing minerals to the surface for other plants to use. It can also provide habitat for beneficial insects and microorganisms.

Cover crops can be grown in between rows of a vegetable crop, as a perennial in orchards and vineyards, or fall-planted to be tilled into the soil in the spring. Now's the time to begin to plan and plant your fall cover crop.

Many plants can be used as cover crop, including legumes that obtain their nitrogen from the air and can provide as much nitrogen for your next crops as fertilizer. Legumes need to be tilled into the soil at peak bloom, but before seed has set. Examples of legumes good in this area are crimson clover, Austrian field peas, hairy vetch, and annual and winter rye.

You can buy most of these seeds locally or get larger amounts and a greater variety in Territorial or Johnny's seed catalogues.

Q: Here's a follow-up to the perennial question of what to do about slugs. Readers have inundated me with their methods of controlling the slug population, and I thought I'd pass along a few of the suggestions. None is scientifically tested, but if something works for you, why not use it?

A: One reader says there's a ridiculously easy way to defeat slugs, particularly for Northwest coffee drinkers. She collects all her household coffee grounds, and then sprinkles them around all her plants. Gone, says she, all those slimy plant devourers! If you aren't a coffee drinker (one of the only two in the Northwest, I think!) there are coffee shops that will give you their used coffee grounds for free. Just ask.

Several people suggested using wood ash to surround a planting area. They say it works well but has to be renewed when it rains. Not a problem this year, but it could be a lot of work in wetter summers.

Diatomaceous earth, a natural product composed of ground-up shells, works quite well, say others, but has the same problem with rain.

So, it's up to you, readers, to find what you think works well. If you are buying slug bait, remember to buy ferrous sulfate (iron sulfate), which is harmless to pets and wildlife. The one with metaldehyde is deadly to pets, animals, birds and humans.

Q: I was recently introduced to the concept of gleaning. Is there any gleaning going on in this area?

A: You bet your peck of tomatoes! When it comes time to collect apples to press into cider, I keep my eyes open for ripenin g apples that don't appear to be used by the owner. If I deem it reasonable, I will ask the owner if they're going to use all the apples, and if not, could I pick some or gather them from the ground. I have never been turned down, as most people with large apple trees can't possibly use all their produce. And fallen apples attract varmits you don't necessarily want on your property.

A fine way to help out in the community is to volunteer to be part of the gleaning program at the Bellingham Food Bank. You sign up, and then when there's a glean, you'll be notified by email. Though most of the food gleaned will go to the food bank, the gleaners are almost always able to take some of the produce for themselves. Every type of food is harvested.


Ask a Master Gardener will appear in The Bellingham Herald weekly through the summer growing season. If you have a gardening question you'd like answered in the column, please email it to

Master Gardener Kathleen Bander is a resident of Bellingham and life-long gardener. For more information on Whatcom Counry Master Gardeners, go to

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