Marin Master Gardeners
University of California
Marin Master Gardeners

A hill o' beans

Beans are one of the silent workhorses of the vegetable garden, providing plentiful crops while simultaneously enriching the soil with much-welcomed nitrogen. These food crops are part of the legume family, a group of plants whose roots have special nitrogen-fixing bacteria. Marin gardeners adore this magical feature because nitrogen is one growing necessity in short supply in our soil.

Both pole and bush bean varieties provide abundant crops. Photo by Marybeth Kampman.
Both pole and bush bean varieties provide abundant crops. Photo by Marybeth Kampman.

Beans come in bush varieties up to two- feet tall or, for space-challenged gardeners, there are the beloved pole varieties that rocket twining vines five to ten feet skyward so long as they have a sturdy support on which to climb. Pole varieties take up less of a footprint than bush varieties, and they typically produce a larger crop. Growing pole varieties does not require any fancy contraptions. Any sturdy support will do: an old ladder, bamboo poles or sticks tied together to form a tepee, old wire or slatted wood fencing, or heavy-duty nylon string strung between two makeshift poles.  

Beans are easy and satisfying to grow in summertime heat. They will grow in most any soil but prefer it well drained and chock full of organic material. Plant bean seeds directly into the garden and protect the sprouts from snails. If watered regularly, beans are seldom bothered by pests.  
    
Most gardeners harvest beans before the seeds are mature, nibbling instead on the delicious pods that contain the developing seeds. Snap beans are picked when the seeds are tiny and the pods succulent. Shell beans are harvested when the seeds are tender and the seed pod is thick and leathery. Once legumes begin to fruit, it is important to harvest regularly. Bean plants that get to the dry-bean stage will slow down or even stop producing. Keep an eye on the bottom of the plant where the first pods form to be sure no pods went unplucked. And at the end of the season, don't forget to leave a few on the vine to dry so you can replant those seeds next year.

Varieties to consider

There are a multitude of bean varieties to try, most suitable for areas that get hot in summer. However, scarlet runner beans -- whose pink beans are tasty and whose brilliant red flowers are striking -- grow in foggy areas. And fava beans, treasured both for their delicious taste and superior nitrogen-fixing abilities, grow in winter. Heat-loving beans include the fantastic flat-pod Romano and the colorful trio of Blue Lake or Kentucky Wonder greens, Yellow Pole Wax, and Purple Peacocks. (Spoiler: when you cook purple beans they turn green!)


By Marie Narlock

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