Henry Homeyer: Tips for planting a spring vegetable garden

Although there are many old sayings such as, "Plant your potatoes when the oak leaves are the size of a mouse's ear," I would rather depend on soil temperature and calendar dates. Besides, who really knows the size of a mouse's ear?

Mid-May is good for cool-weather crops such as spinach, peas, lettuce, onions, potatoes and broccoli-family plants. I don't put heat-loving plants — such as tomatoes, cucumbers, zucchini, corn and peppers — in the ground until it is at least 60 degrees. The date for this is usually around June 10 here in chilly Cornish Flat, New Hampshire, but may be sooner depending on where you are.

I know you are anxious to get your crops growing, but tomato seedlings put in chilly soil when nights are still cold are not happy. They don't do much growing and may take time to recover. I’d rather keep them sitting on a sunny lawn all day and bring them in at night.

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Before you think about putting plants in the ground, please harden them off. That means introducing them to full sun over the period of a week. Start with morning-only sun, then add an hour of afternoon sun and work up to a full day of sun. Cloudy days allow you to keep them out all day, but watch out for rain. If they are in a flat that holds water, they can get too wet or get beaten flat.

I also consult with a biodynamic calendar that recommends when to plant the different categories of plants: flower, fruit, leaf and root. The one I use, called "Stella Natura," uses the position of the moon, stars and planets to determine what to plant — or, more importantly, when to plant nothing.

Ask at the nursery where you buy your plants if they have been hardened off. Things such as cabbage and lettuce probably are already hardened off and sitting outside the greenhouses on tables. If so, they are ready to plant anytime, but there's no harm in asking.

While keeping your plants happy in their little plastic six-packs, you might want to water with a dilute fish fertilizer solution. At the nursery they generally are given dilute chemical fertilizer, but I find fish fertilizer works well, and they grow strong and tall. I like the brand Neptune's Harvest.

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Few of us have enough garden space for everything we want to grow, so we have to make decisions about how many tomatoes or potatoes we should grow. Ask yourself what your favorites are, or if you will actually can or dehydrate tomatoes if you put in a dozen plants and don't eat them all in salads and sandwiches. Be realistic.

Don't crowd your plants. Tomatoes need 24 inches between plants. Potatoes need 18 inches, onions 4 or 5 inches in rows a foot apart. What happens if you crowd them? You'll get more onions, but smaller ones. Peppers, on the other hand, only need 12-inch spacing, as they like to actually touch their neighbors.

A good reference guide is "The Vegetable Gardener's Bible," by Vermont author Ed Smith. Even I use it from time to time, and I’ve been growing vegetables for decades. Ed and his wife, Sylvia, really know their stuff, and they buy very few vegetables in a year.

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To maximize garden space, I plant quick-growing plants such as radishes and lettuce in between or around slower-growing things such as tomatoes. Plant a tomato, put it in its 54-inch support cage (never use small cages), then circle it with lettuce starts. The lettuce will be ready to eat before the tomato is big enough to shade them. I just planted my onions, and planted lettuce in the spaces between rows of onions. Don't plant things in your asparagus patch, despite all that space, as asparagus hates company.

To maximize production, think about growing vertically: cucumbers, squashes and pole beans. If you do this, be sure to put the trellis on the north side of your garden to avoid shading out other plants. You can buy a trellis or build your own using posts with attached chicken wire or welded wire with square openings.

If you want to grow hot peppers or eggplant, think about providing them with extra heat. No, not blankets. Choose dark rocks the size of a loaf of bread and place them near your plants. They will absorb heat from the sun and radiate it back during the night. You can also cover them with ReMay or row cover, a light synthetic fabric made for gardens that holds in heat and keeps bugs off.

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Most years, I have a pest called the striped cucumber beetle. It dwells in the ground and comes out at night. If I were to plant cucumbers, pumpkins or squashes by seed in the ground, the beetles would arrive and eat the first two leaves off right away, killing the plant. So now I start them indoors by seed and let them develop four to six leaves before I plant them outside. Sometimes I cover them with ReMay, too.

Potatoes are plagued by the Colorado potato beetle almost anywhere. I minimize the problem by planting my potatoes later in the season than my neighbors. I look for these striped beetles, their larvae and orange egg masses. I hand-pick them and then drop them in soapy water. I do that early on, as they multiply quickly, and each beetle will lay many eggs.

Being a good gardener takes time, but don't be discouraged. One day you will retire and have plenty of time — even if maybe not enough energy! Just remember to take time to enjoy what you do!

Henry Homeyer's blog appears twice a week at gardening-guy.com. Write to him at P.O. Box 364, Cornish Flat, N.H. 03746. Please include a self-addressed, stamped envelope if you wish a mailed response. Or email [email protected].