I love planning my garden. Every year, I have to try something new, whether it be a different color of cabbage, or perhaps something I’ve never eaten before. Of course, if I’m not familiar with it, there’s a chance I’ll see a pest I haven’t met before. That’s when it’s tempting to bring out the pesticide artillery, although I do know better.
A few years ago, I found a quote from a Cornell University garden fact sheet:
“Relying heavily on the use of any pesticide is a rash, unecological practice.”
They aren’t just talking about conventional chemical pesticides, but all of them - even organic ones. Sometimes you don’t have a choice, but the idea is to set your environmental stage so it’s less likely you’ll need them.
Take a few steps before putting any plant in the ground, whether it be in native soil, a large pot, or a raised bed. If you can help it, don’t put the same type of plant in the same spot year after year. The odds are you’ll be building up problems, since pests that attack one member of a genus or species are likely to attack many more members.
Then, how’s the soil? If you’ve grown plants in it before, it’ll need some refreshing. Plants take up nutrients when they’re growing. Adding good compost is a terrific way to replenish them. If you’re growing plants in pots and saw pests in a pot last year, don’t re-use that soil unless you can sterilize it. And make sure to thoroughly clean the pot. No need to look for trouble. That’s not really possible with a raised bed, but again, if you can avoid using a similar type of plant in that spot – like don’t follow brussels sprouts with broccoli, or onions with shallots – then you’re cutting down the likelihood of pests.
If you’re creating a garden from scratch, make sure you have good drainage. This is possibly the most important factor in plant health. Plants – shrubs, trees, vegetables, even grasses – will all die if they sit in muddy, airless holes.
Even though we’d like to provide everything a plant could possibly want, it’s not a good idea to overdo. If you’ve already amended your soil with compost, you probably don’t need to add a ton of soluble fertilizer.
Too much nitrogen results in an overly succulent plant that’s a magnet for pests. It can also deter a plant from producing fruit, and instead, you’ll just get leaves – not necessarily what you’re hoping for.
On the other hand, with too little nitrogen you’ll get weak, yellowed plants.
Make sure whatever you’re growing has a good chance of survival under our challenging conditions. Tomatoes, for instance. Who doesn’t want a luscious, deep red tomato? And we can grow them here, but we can’t just stick them in the ground and hope for the best. Not all varieties are good choices for this difficult climate.
For one thing, they need to be in the ground by the beginning of April. Think about summer in the Mojave Desert.
Once the hot weather hits, most fruit that’s still green is going to poach on the vine, and never ripen. So look for varieties that have the shortest number of days from seed to finished plant. The shorter, the better, and in general, smaller tomatoes perform best.
Last year, so many gardens experienced the attack of root knot nematodes. I know I hadn’t seen them in my garden before last season. These microscopic round worms invade roots and ultimately kill plants. They aren’t insects, so insecticides won’t work on them. There are some organic products on the market that claim to control them; you can also buy other parasitic nematodes to eat the bad guys, and you can try growing French marigolds as well. Root knot nematodes have a huge host range, but they love tomatoes. Since they’re hard to spot before they’ve done significant damage, try getting varieties that explicitly say they’re “nematode resistant”.
Planning the garden is one of the most enjoyable things I know, but planning to prevent or deal with pests - that makes it even better.
For KNPR’s Desert Bloom, this is Dr. Angela O’Callaghan of the University of Nevada Cooperative Extension.