Margaret Lauterbach

Pea vines can disrupt the growth of next year’s veggies

Margaret Lauterbach
Margaret Lauterbach

Gardening may be simple, such as a cave dweller poking a stick in soil and dropping in a seed, then waiting for rain. Or gardening can be complicated. I’ve just entered the complicated region. Could not figure out why beans and okra germinated sparsely in one bed, each row planted twice, germination still very poor.

Last fall I mulched that bed with spent pea vines, confident that they would not carry the residue of persistent herbicides that are often sprayed on grains producing straw. Now I’ve learned that pea vines themselves are allelopathic, affecting “the growth and development of agricultural and biochemical systems.” Learning the hard way, apparently.

By definition, the effect of allelopathic plant-produced chemicals may be stimulating or toxic. Most of us know about the destructive allelopathic effects of black walnut trees, but I never thought to investigate pea vines. I still have unbound bales of pea straw. I’ll use them to add organic matter to my compost pile, and hope they’ll lose that deleterious effect after thorough composting.

Another use for them might be as organic herbicides, spread on weeds to control or kill them. Many plants contain or release chemicals that inhibit other plants, even their own species, but that effect is usually ineffective after a few weeks. Black walnut leaves spread on quack grass killed that grass, but did not prevent runners from starting new quack grass in about two months.

This inhibiting effect of pea vines seems to be only affecting seeds. Transplanted tomatoes and peppers in that bed are doing just fine. But I certainly hate to see so much bare soil in the growing season.


Just received the fall catalog from Territorial Seeds, and they know how to make a gardener’s mouth water. I’m so overwhelmed with the beauty of my scarlet kale plant I’m very tempted to order more seeds for that variety. I haven’t harvested any to eat yet, but Stella Schneider, also impressed with the beauty of the plant, says it’s delicious.

This kale’s more purple than scarlet, in my view, and Territorial’s catalog says its color deepens with cooler weather. Its color indicates it’s loaded with anthocyanins, anti-oxidants, anti-inflammatory and anti-carcinogenic matter. I may also start some light green Romanesco cauliflower (some vendors call it a broccoli), and hope to harvest a head in mid winter. A few years ago I harvested a head of this delicious and gorgeous vegetable on January 1. I had not cleaned out the garden earlier in Fall.

Another tempter is Territorial’s mulberry cauliflower, and some cabbages. I have a lot of seeds on hand, but new varieties are irresistible. Kale, cauliflower, cabbage, broccoli, collards and Piracicaba must be started from seed indoors, since the soil is too hot for their germination in the place they’re to grow. Another tempting seed is one for Brussels sprouts, hoping it will produce before killing frost. Those brassica seeds germinate best at temperatures around 45 degrees F. Indoors is not that cool, but it’s a better temperature for their germination than 100 degrees F.

This is a weird gardening year for me. Over population of squirrels means they dug up my seedling transplants to bury their peanuts (then they forgot them, and they are rotting in the ground, so nobody wins). I’ve had to plant and transplant over and over again, trying to save seedlings tossed aside. I had already given away my extra plants, so I’m growing fewer Piracicaba, Tuscan kale and broccoli plants than I’d planned because of the squirrel depredation.

We have enough for ourselves, but we usually send a lot of extra greens and other vegetables to the Idaho FoodBank

I have planted and replanted sweet potato slips, finally resorting to installing wire baskets over sweet potato starts, and pegging them down with earth staples. I did lose several slips and pieces of sweet potato, as well as some Yukon Gold potatoes the squirrels dug up and bit into, looking for the “nut” inside. They must have thought they were apricots. If humans are to survive on earth, squirrels may have to be reduced in number. Other Boise gardeners are also complaining about squirrel damage too.

Send garden questions to or Gardening, The Statesman, P.O. Box 40, Boise, ID 83707.