Your Guide to Growing Tomato Plants From Seeds

Here's when to start your seeds so you can get your germinated tomato plants in the ground on time when the weather warms up.

The difference between a home-grown and store-bought tomato is like comparing a cashmere throw to an airplane blanket. Biting into a salad made with tomatoes planted and grown in your own garden is a sensory experience and one of the summer's greatest pleasures. Of course, there is some hard work and care that must happen before you're ready to slice into your harvest. First, you must pick what kind of tomatoes you want to grow, learn how to grow tomato plants from seeds, get sprouts in the ground, and pollinate them when they're mature to ensure a bountiful supply.

tomato plants
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Find Your Last Frost Date

When planting anything, including tomatoes, first learn your last frost date, which is the average date of the last freeze in spring. After you find this date, and if you are starting from seed, count five weeks back and mark your calendar. According to Charlie Nardozzi, garden expert, author, and radio host, tomatoes need about four to six weeks of indoor growth before they are ready to be transplanted into the garden.

If you decide to start with young plants, put them in the ground in late spring—or when nighttime temperatures consistently remain above 50 degrees.

Pick Your Variety

Now that you know your date to sow seeds (or put seedlings in the ground), you can pick out the type you want to plant. Nardozzi loves heirlooms like Persimmon, Tasmanian Chocolate, and Speckled Roman because of their vivid colors, unique shapes and, of course, their taste. But classic cherry and beefsteak varieties are great, too.

Choose Between Determinate and Indeterminate Tomatoes

Your space and how much effort you're willing to put in will help you decide if you want to grow determinate or indeterminate tomatoes. Determinate varieties will grow to about 2 to 3 feet and produce fruit at one time, while indeterminate will continue to grow higher and produce fruit continuously.

How to Plant and Grow Tomatoes From Seeds

As mentioned, be sure to start your tomato seeds about five weeks before your last frost date so they can germinate and be ready to be placed in the ground by the time the weather is warm and conditions stabilize.

Sow the Seeds

Place the seeds in 2 inch x 2 inch biodegradable cow-pots. Be sure to keep them in a warm indoor place that gets at least six hours of sun and water them regularly—the same goes for when they are (eventually) moved outside.

Once the seedlings germinate and break out into a "y" shape, thin out the weaker of the two sprouts by cutting it with scissors close to ground level, says Nardozzi. Then, let the remaining sprout grow until it is three times the height of the pot, about 6 inches. Now, transplant this seedling into a pot one size larger.

Pro tip: For faster germination, place a heating mat for seedlings under the pots.

Harden Your Plants

Your tomato plants should be eased into moving outdoors full time; this is called hardening off your plants. To do so, start by bringing them outside in the shade for an hour or two, gradually increasing the time and the amount of sun over a week period. "This will get them used to the sun and the wind," says Nardozzi.

You should also hold off on putting your tomato plants in the ground if the weather is unstable. "Cold, rainy weather is a death knell for tomatoes," says Nardozzi. "Delay transplanting if that's what's happening at that time or protect them in the garden with fleece wraps."

Mix the Soil

Once your plant is hardened and the weather has warmed, it's time to take them out to the garden. If you're planting in the ground, it's a good idea to prepare the area about two weeks beforehand. Dig a hole approximately 1 foot deep and mix in some compost or manure. If you're planting them in a container, use a mix of potting soil and compost in the pot, says Nardozzi. Plant the seedling deep enough to cover the stem up to the first set of bottom leaves and water. Water it and fertilize with an organic plant food weekly for plants growing both in the ground or in a container.

Plant According to Size

An easy way to unsettle your tomatoes is by planting them in a pot that is too small or not using a caging or staking system for tall varieties, says Nardozzi. Pots should be 18 inches for determinate and 24 inches for indeterminate; stakes or cages should be put in the ground when you plant them.

hand pollinate tomato plant
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How to Pollinate Tomato Plants

Pollinating your tomato plants by hand will help them produce more fruit, as the natural pollination process can often be limited by lack of air movement or low insect numbers.

Why You Should Pollinate Tomato Plants

Tomato plants are different from other edible varieties because they do not require wind or insects to pollinate and fruit. "They have both male and female parts and are capable of producing a crop of fruit on their own," says Kelly Funk, the president of Park Seed. "Multiple plants are not required."

This means that the transfer of pollen occurs in a single flower without the assistance of wind or insects. Despite this fact, tomato plants still need sufficient wind to transfer the pollen within the flower. "If there isn't enough wind, high temperatures, or excessive moisture or humidity, pollination may not occur," Funk says. Pollinating by hand helps to ensure the process takes place and your plant produces fruit.

How to Hand Pollinate

Pollinating tomato plants by hand is relatively straightforward. "A simple shake to the stem will gently distribute the pollen," Funk says. "If no pollen is released, shake a little harder or flick the stems close to the base of the flower. This motion imitates the breeze of natural pollination."

You can also use an electric toothbrush to apply a gentle vibration. To do this, place the toothbrush behind the open flowers and shake the pollen for just a few seconds. "Some pollen may fall and you can catch it to apply by hand," Funk says.

Once you've kicked up some pollen, use a small paintbrush to gather and distribute it, just like an insect would do. "Just be sure to use a brush with natural bristles instead of plastic so the pollen will stick to it. A cotton swab can also be used with this same method," Funk says. Make sure you wash the tools off before repeating the process with different tomato varieties to avoid cross-pollination.

When to Pollinate

The best time for hand pollinating is mid-afternoon on warm, sunny days with low humidity. Funk says to repeat the process every week on new flowers to improve pollination rates.

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