Margaret Lauterbach

When planting beans, check to see which ones cross-pollinate

Statesman gardening columnist Margaret Lauterbach is taking some time off. She’ll be writing again in January. But she’s checking her email, so if you have questions, email her at Meantime, we’re repeating some of her most popular advice.

I’ve been busy planting several varieties of beans. Can they cross-pollinate?

The regular Phaseolus vulgaris beans may cross, even pole beans to bush beans or vice versa. But others I’ve been planting are “black” garbanzos (botanical designation is Cicer arietinum), Michels Cowpea (Vigna unguiculata) and Dixie speckled butter pea (actually a baby lima bean, Phaseolus lunatus). According to Suzanne Ashworth’s “Seed to Seed, “ there’ll be no cross-pollination between P. vulgaris and P. lunatus, V. unguiculata or C. arietinum. Cicer is an Old World bean, Vigna is from Africa and the others are New World.

The lack of cross-pollination is good news for those of us who want to grow similar crops in limited space. My snap beans (Slenderette) can cross with Good Mother Stallard pole beans and perhaps with the Zuni gold beans I planted for dry bean use, but if they cross it’s of no concern because we’ll just use them ourselves. Cross-pollination will show up in the coloring of the beans, and it’s more of a concern to commercial growers and seed savers.

Reaching interior rows on my 4-foot-wide beds is quite a stretch, so I’m using a piece of white PVC pipe and rolling seeds through it after placing it where I want the next plant, then pushing beans into wetted soil with the tip of my long-handled trowel. A stick would work as well, I suspect. They’re a little shallower than they should be, but I think deep enough.

The garbanzo seeds came from Nichols Garden Nursery, and they included a small packet of inoculant to increase fixation of nitrogen from the air. All of the above are legumes that fix nitrogen from the air to some extent. The inoculant increases that activity. Instructions recommended dosing moistened garbanzo seeds with the inoculant, so I used the same method I use to make bean sprouts: a square of nylon net over the mouth of a canning jar, the net held in place by a jar ring. Then a flush of water and emptying it before removing the garbanzos.