Master Gardener: Time To Start Seeds Indoors For Vegetable Gardens

Ask Tom Ingram a Master Gardener

"I don't know why, but I can't wait to start my garden. I usually buy transplants in town, but this year I want to start something from seed. How do I do that?" -Gl

That time of year. With cool-season vegetable planting season from mid-February to mid-March, the window to start those indoor seeds is closing if you haven't already. But the good news is that many of these plants can be grown directly in the ground. These crops include carrots, turnips, turnip greens, lettuce, peas, spinach, radishes and turnips.

If you start seeds indoors, you should start them five to six weeks before you plan to take them outside. This means that if the planned planting date for your warm season crop is April 15, you should start planting around March 1.

Starting seeds can be a little tricky and there are tons of seed starting gadgets out there, but in reality you can start seeds with almost anything. Legit seed starter trays are great, but eventually any type of container will work, such as a used yogurt or butter container.

Personally, I like to use peat pots because when the time comes, you can plant the whole pot in the ground. But these little single-use plastic cups are also great for starting seeds.

Once the seed pots are lined up, you'll need a seed mix. Seeding mix is a much easier and more suitable medium for starting your seeds. Its light texture makes it easy to reach small roots. If you're using a seed starter mix, it's a good idea to fill your pot halfway with regular potting soil and then top it up with seed starter mix. This will help give them a good mix of media to start their gardening journey. Be sure to soak this mix in water before planting your seeds, as the initial seed mix may change slightly the first time you water. If you've been through it, you know what I mean.

After planting your seeds in their new temporary home, you should find a warm spot with plenty of sun. Most seeds germinate quickly when the soil is warm. Seventy degrees would be fine, but a little warmer wouldn't hurt. Cultivation mats are available for warming the soil. With a heat mat, these cucumber plants will begin to sprout in a day or two. Without it, it might take a little longer. Be sure to close the seed starter heat mat and remove it once the seeds have germinated.

Seed starter bowls usually come with clear plastic lids. They are great because they help retain not only heat but also moisture. However, once your seedlings start to grow, you will need to remove the cover to give them room to grow and air circulation. Also, these warm, humid environments are great breeding grounds for fungus, so don't leave them out too long.

Light is a key factor for your new little buds. A grow light makes this easy. If your grow light is framed or you hang it above your plant, you'll want the light as close to the plant as possible. This means increasing the light as your plants grow.

If your new shoots look long and skinny, this is your way of telling them that they need more light. If you have a light crop, plan to leave it on your seedlings for 16-18 hours a day. We currently get about 12 hours of light per day so you can see how grow lights can speed up your kids.

And plan to rotate your plants under the lights unless they are getting the same light. Without rotation, trees under direct light grow to shade trees at the edges. Then alternate between lighting hotspots for the most consistent results.

Planting days fast forward. One thing that many gardeners overlook is a process called "curing." During hardening, plants are gradually brought out. For this, there is a plan to gradually introduce them outside. First, perhaps choose a partially shaded area and let them sit for a few hours. Gradually increase their exposure to the sun and elements over a week or so so they can prepare for their new home.

You need to remember that your new seedlings live their best lives since you pamper them with food and water. If they are not gradually introduced to the fresh air, it may be too much for them and they will not make it. Introducing them gradually gives you a better chance of success.

If starting your own plants from seed seems a little overwhelming, we have a great selection of vegetable plants at our annual plant sale/fundraiser. Visit tulsamastergardeners.org for more information. See you soon in the garden!

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You can get answers to all your gardening questions by calling the Tulsa Master Gardeners Helpline at 918-746-3701, visiting our Diagnostic Center at 4116 E. 15th St. or emailing us at mg@tulsamastergardeners.org.