Getting Tomatoes Off to a Great Start
It’s time to start growing your tomatoes from seed! Tomatoes are pretty easy to grow from seed; that’s why they’re such a popular plant to grow for first-time gardeners. While growing tomatoes from seed is easy, there are a few things you can do to give your seedlings a good head start so they’ll be healthy and productive this summer.
Use a High-Quality Starter Mix
Good quality soil is vital for all your seedlings, and a starter mix is specifically designed to prevent seeds from developing diseases or fungal problems when they’re young. There are plenty of great soil options to choose from here at Mother Nature.
It’s best to start with dampened soil in clean planting cells. The soil should feel a bit like a wrung-out sponge, not too wet, but not too dry. Create small holes, about an eighth of an inch deep and about an inch apart in your planting cell. A chopstick or pencil is about the right size to create the holes.
Tomato seeds are pretty light and thin, so they can be tricky to work with. If you dampen the tip of your pencil or chopstick and gently tap it against a seed, it should pick up just one. Pop one seed into each hole, and then fill them up with soil.
Water your seedlings lightly, and then make sure the trays are covered with a humidity dome.
Keep Your Growing Tomato Seeds Warm
Tomatoes like warm weather. It’s not critical, but using a seedling heat mat can speed up the germination of your tomatoes by up to a week!
If you don’t have heat mats, position your tomato seedlings somewhere in your home that stays consistently warm and doesn’t get too many cold drafts from doors opening and closing.
It’s a good idea to remove the humidity domes from your baby seedlings for a few hours each day for air circulation. Make sure you replace the humidity domes at night to help maintain air temperatures until your plants are big enough not to dry out overnight.
Give Tomato Seedlings Lots of Light
Once your tomatoes start to sprout, it’s time to get them under grow lights. Tomatoes need tons of light. With just window light, they’ll get tall, weak, and spindly. It’s best to use grow lights for starting tomatoes at home.
Position your grow lights so that they’re just barely above the tops of the humidity domes, and they should be on for 12-14 hours per day. Automatic light timers are a lifesaver.
Give Tomato Seedlings Space
Once your tomato seedlings are 1-2 inches tall and have developed their first set of true leaves, it’s time to transplant them. If you were growing multiple tomatoes in one starter cell, it’s time to move them into their own growing space. Tomatoes use lots of nutrients and water, so they’ll suffer from too much competition with other plants.
Increase the size of the growing space for your tomatoes incrementally, though. Don’t take them from the starter cell to a 6-inch pot. Move them up to a 1 or 2-inch pot, then 3-4 inch pots, and so on, as they grow.
This is also an excellent time to move your growing tomatoes into high-quality potting soil. Starter soil doesn’t have much for nutrients, and your tomatoes will need those now to grow healthy and strong.
Same as before, it’s best to start with pre-dampened soil and create small holes, about an inch deep, with a chopstick or pencil. Using the same chopstick or pencil, gently push it down into the soil beside the seedling, about half an inch away. Then gently grasp a leaf, and use the pencil to lever up under the plant to loosen the soil while gently pulling it up by the leaves.
The reason for pulling on the leaves is that the plant will grow more leaves if you break or tear one, but they only have one stem. The stems are quite fragile at this stage, and if you break the stem, the tomato plant is a write-off.
Gently place the roots of your tiny seedling into the hole in its new container, and then use the pencil or chopstick to fill the hole with soil.
Water Your Tomato Seedlings Consistently
As seedlings, tomatoes use about the same amount of water as any other plant. But as they start to get bigger, you might notice that they may dry out faster than other young plants. They use a lot of water to grow strong enough to create those delicious tasty fruits.
It’s essential to maintain consistent watering for your tomatoes, even when they’re small. Inconsistent watering causes stress to the plants, and once your tomatoes start to produce fruit, the stress can lead to blossom end rot.
Get the Air Moving
Once your tomatoes are growing in their individual containers, you need to get the air moving even more. Take off the humidity domes, and set a small fan nearby, aimed at the plants on a gentle setting, to keep the air moving through your growing tomatoes.
Damping-off is a fairly common problem with tomatoes. It’s a fungal problem that happens when things get too humid, and there’s not enough air circulation. Keep a close eye on your plants for signs of damping off. Once it’s gotten started, it’s hard to stop, and it can destroy your whole crop.
A fan also helps your seedlings develop stronger stems, so they’re more resilient in the wind once they’re outside.
Harden Off Growing Tomatoes Gently
Before you plant your tomatoes outside, make sure you harden them off sufficiently. The shock of being transplanted outside straight from living in a warm and calm house is not good for any plants.
Start hardening off your plants 2-4 weeks before the last predicted frost. Start by setting them out for 1 or 2 hours in the warmest part of the day, in a shady spot. Gradually increase the time and their sun exposure. Help your tomatoes adapt safely by working them through this hardening off schedule.
- First two days, full shade, 1-2 hours
- Days 3-4, dappled shade, 1-3 hours
- Days 5-6, full sun, 2-3 hours
- Days 7-14, full sun, increase from 3 hours to 6 hours over the week
- Days 14-21, full sun, at least 8 hours per day, at the end of the week leave them out overnight if nighttime temperatures are consistently above 10°C.
If you haven’t gotten your seed starting supplies yet, you might want to get to it! The demand for seeds and starting supplies is high again this year, so don’t wait too long. It’s also time to start thinking about getting your seed potatoes! Don’t leave it till the last minute, or you may not have much luck getting any at all, never mind the particular varieties you like.