Question. Mike: What is the best time to put tomato plants in the ground?
- ---Ray in Hatfield, Pa.
- ---Chuck in Leesburg, Virginia
- ---Ray and Melissa in Plainsboro, NJ, just across Route 1 from Princeton.
- --Dan in Swarthmore, Pa.
- --Kevin in Cochranville, PA
1. Thin them out! This is the hardest thing to do in gardening, but if you leave more than one plant in each pot, none of them will thrive. If you've been gardening for a good long time and have done this kind of thing before (successfully), use a sharp knife to cut straight down through the root mass, then pot each plant up again separately. (Don't try this if you a newbie and NEVER try and pull them apart!) A safer bet is to just snip the weakest ones off at the soil line with a little pair of scissors. Lose the ones with the thinnest stalks—unlike us, thick stalks are good.
2. Don't rush the season! Actual frost isn't the only consideration. Tomatoes are tropical plants that don't like to catch a chill. So don't even think about planting them outdoors until nighttime temps are in consistently the fifties. My 'last average frost date' is May 15th (you should be able to find yours online; otherwise, just contact your local county extension office), but I often wait until June 1st if Spring has been a little slow. I'll get ripe tomatoes at the same time as if I had planted earlier in the season, and the plants will not sulk nearly as much.
3. 'Harden off' your tomatoes before you plant them. Take the potted plants out in the morning, water them well, place them where they'll get some sun and then bring them back inside that evening. Repeat this for a few days, ideally increasing the amount of sun they get each day. Then leave them out all night for another couple of days (unless overnight temps drop below the mid to high forties, then bring them back in—tomatoes have very little sense of humor about these things). Don't neglect this step! Plants that go right from a warm home or greenhouse into the unpredictable outdoors often suffer severe early season setbacks.
4. Save your eggshells for them! (Or, yes—crushed oyster shells, if you got 'em.) Both are great natural sources of calcium—a nutrient often greatly lacking in our soils but that helps you grow better tomatoes two ways! 1) It helps the plants regulate their water needs, preventing nasty conditions like cracking and blossom end rot when the weather is too wet, too dry or too roller-coaster. And 2) Tomatoes need calcium to achieve their full flavor potential. I put the crushed shells of a dozen eggs in each planting hole. No eggshells? Take a five-gallon bucket to any restaurant that serves breakfast and you'll get all you need in one day. Otherwise, put a handful of a calcium-rich natural fertilizer, like "Tomatoes Alive" from Gardens Alive in the hole when you plant. (Either way, toss in some compost too!)
5. Pick the proper spot. Before you put your tomatoes in the ground, take a good look at their potential planting areas and give them the site that gets the most morning sun, so the wet-with-dew plants can dry off first thing in the morning; it's a great way to prevent disease problems before they start. Other, less-disease prone plants can wait a little longer for the sun to get to them.
6. Rotate your crops. Speaking of disease, you should also try and plant your tomatoes in a spot where tomatoes have not grown the past couple of years. If that's impossible, remove as much of the soil as you can and replace it with a mix of half compost and half topsoil—or half garden soil from tomato free areas. Otherwise, your plants may wilt from a common disease that builds up in soil where tomatoes are frequently planted. If that's already happening (the plant leaves begin to turn yellow at the bottom) and you've already used every possible and/or potential planting plot, try growing in BIG containers (at least 12 to 15 inches across).
7. Space them far apart. Be sure to give your precious plants LOTS of room. With beefsteak types and big heirloom varieties for instance, those little starts will eventually produce vines that are ten to fourteen feet long. Plan for that FULL size now, otherwise the plants will be too crowded and disease will take its toll. (If your space is limited, stick with determinate, 'bush' type varieties that stay more compact.)
8. Cage them. Surround each plant with a big cage so the tomatoes don't lay on the ground; and stake the cage so those big vines don't pull it down. Tomatoes are vines—they don't grow upright naturally—so you have to provide good support. Those flimsy little things they sell as 'tomato cages' won't do the job. Make a big circle out of sturdy 5 or 6 foot-high animal fencing (NOT chicken wire) instead; it's sold in 25 and 50-foot long rolls at virtually every big home center. A six-foot length cut from the roll makes a great cage for big tomatoes. Five foot long is fine for smaller varieties.
9. Bury them DEEP! Tomatoes are unique in that any part of their stem buried in the ground will grow auxiliary roots to take up more water and nutrients. So be brave, pull off the bottom leaves and bury a good two-thirds of the plant underground. You heard me! All you need is two to three inches aboveground. And always plant in the evening, never in the morning; you want to give your tomatoes time to get acclimated before they experience a full day of burning sun.
10. Compost against disease! When you're all done, spread an inch or two of your highest quality compost over the surface of the soil under your plants. This will prevent weeds, feed your tomatoes, and—perhaps more importantly—the billions of living organisms in that compost will prevent dread diseases from attacking your plants.