Avoid These Common Mistakes When Transplanting Tomatoes At All Costs

Sometimes we learn best from our failures. Sure, you can read about how to do everything the right way, but the mistakes that you'll always remember are the ones you made yourself. After over 20 years of gardening, 13 of which have been as a Master Gardener, I think I've made almost all the mistakes. One that stands out in my mind is the first year I grew tomatoes from seed. I thought I had done everything right: They were healthy and strong but still pretty small. In my eagerness to get them in my freshly-tilled garden, I planted them too early in the season the day before a big storm was expected. Twenty four hours after placing my sweet little seedlings in the ground, I watched as they got pummeled by golf ball-sized hail. A few weeks later, I bought 20 new tomato seedlings to replace the ones nature smashed.

Planting too early is just one common mistake gardeners make when transplanting tomatoes. Failing to harden off your home-grown plants before placing them outside is a recipe for disaster. Selecting a less-than-ideal location for your tomatoes will also result in big problems and a small harvest. Avoid these mistakes by carefully planning your planting time, preparing your seedlings for transplanting, and choosing the best garden spot.

As House Digest's Garden Editor, it's my job to make sure our readers get the best advice, so here's mine: Never plant too early. Where I live in USDA Hardiness Zone 6, we always get a late frost, and the weather is predictably unpredictable. On May 1, it could be 90 degrees Fahrenheit or we could get snow — both have happened. Since the last expected frost date is an average of the zone's latest frosts each year, it is not the actual last date of possible cold weather. I have two primary deciding factors for when I transplant my tomatoes: It's always after the last expected frost date, and there cannot be any nighttime temperatures below about 50 degrees in the extended forecast. When it comes to transplanting, soil temperature is more important than the last frost date, and tomatoes grow best in soil temps above 60 degrees.

You can harden off your plants in a short period of time, but I like to give my tomato seedlings about two weeks to get fully acclimated to the outdoors. On the first warm day, I put my little plants out for two hours, then four the next day, six the next, and so on, until they are out all day. If there's going to be bad weather, including strong winds or bad storms (like hail!), I leave them inside that day to protect them from damage. Unless we get a cold front or bad weather, they stay outside all day and night until I'm confident the weather is warm enough for them to go in the ground.

Before we get ahead of ourselves and start planting tomatoes all willy-nilly, it's important to choose and prepare the right spot for your plants. My experience with this veggie is that it's tolerant of less-than-perfect soil conditions, but it absolutely does not tolerate a shady location. I've grown massive tomato plants in dense clay soil, which actually works in my favor in the extreme heat of summer because clay holds on to moisture better than sandier conditions. Still, tomatoes won't tolerate soggy soil, and if the ground stays too wet, it can lead to issues like root rot and blossom-end rot if the plant cannot access nutrients in the soil. So, choose a spot in full sun in an area that drains well for the healthiest tomatoes.

To keep them flourishing throughout their lifecycle, you'll need the right fertilizer for your tomatoes. These plants are heavy feeders, and lean soil will lead to weak plants and poor fruit production. I like to keep it simple by mixing compost into the soil before planting and using a tomato fertilizer like Jobe's Organics Granular Fertilizer applied according to the package instructions through the growing season. These specific blends have the right balance of nutrients to help you grow healthy plants and get a bigger harvest.