It's time to order your garden seeds for the upcoming season, if you have not already done so. When ordering seed, one of my major considerations is the disease resistance of particular varieties. At a recent book talk, one audience member was surprised when I admitted that I do not buy my seeds from the local nursery's seed rack: why would I bother to mail-order them, he wondered, when the local nursery has seeds? Selection, selection, selection… I would prefer to choose from 20 varieties of cucumbers rather than one, 500 varieties of tomatoes rather than five, and so on. And it's not just my taste buds, but disease resistance, that drives my purchasing decisions.
Here's an illustration. Powdery mildew or downy mildew can be a problem for some gardeners. It can greatly reduce the productivity, if not essentially kill, certain veggie plants. Good soil management, aeration, and water control can help alleviate mildew in your garden, but may not eliminate it. The climate in my area offers plenty of moist, summertime fog (we call it liquid sunshine). Squash get hit the worst here, followed by other members of their curcurbit family, and sometime peas and even leafy vegetables will get the powdery white patches on their leaves.
You can try any and every legal means of alleviating this, but the easiest way to eliminate powdery mildew and similar plagues is to plant resistant varieties. The good news is that more and more resistant varieties are available every year. Take winter squash, for example. Cornell University and the University of New Hampshire have been leaders in developing mildew-resistant varieties, and more and more of these are appearing in seed catalogs and on seed companies' websites. Johnny's Selected Seeds in Maine has worked particularly hard to develop and promote mildew-resistant squash.
Whether it's squash, or peas, or lettuce, or something else in your garden that is succumbing, try visiting some seed companies' websites. I recommend Johnny's, Territorial Seed Company, and Park Seed as three which have worked hard to add some mildew-resistant varieties. Johnny's has lots of resistant squash, Territorial has a great selection of mildew-resistant peas (many via nearby Oregon State University), and Park Seed always offers seeds for plants that can handle the warmth and humidity of southern gardens. Each of these websites has a search box (as do most other seed companies' sites), and you can just type in "mildew" or "fusarium" or whatever ails you, and then see what comes up.
These diseases can be a real plague and we are fortunate to have a way out. No, the resistant varieties are not likely to be heirlooms, but they are not GMO and often they are available as certified organic seed. Planting hybrid seed is not a crime against nature; it simply means you should not save your own seed for the next generation, because it may not grow plants with the same characteristics next year. Growing hybrids means you need to keep buying seed every year, but when you compare this few dollars with the cost of buying all the food that you should be growing, you'll see that it makes sense. You don't need to be an heirloom hero, though for veggies that you have no disease troubles with, saving your own seeds is wonderful and I recommend it.
I hope that some of you who have suffered from plant diseases finally can grow a decent vegetable garden and get yields that you have only dreamed of before. Happy growing!