How To Start Seeds Under Grow Lights

Skip the expensive trip to buy plants at the local nursery this year. You can grow them yourself! You will be surprised how easy it is to set up a place to start your own seedlings. Let’s talk about how to start seeds under grow lights.

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Shelving and Lights

The basic seed germination set up is a shelving unit and lights. We use plug in LED shop lights for our growing lights and a plastic shelf unit that we put together in a few minutes that we bought from Walmart.

Seed Starting Trays and Soil

You need seed starting trays. We use the trays with seventy-two cells to start the seeds. You will also need a good quality commercial potting soil to fill the trays.

Before loading the soil into the grow trays, the soil needs to be moistened. “Moist enough” means that if you grab a handful of soil, squeeze, then release, the soil should hold together in your hand.

Once this is accomplished place the soil into each cell, making sure the cells are completely full. If dry soil is put into the cells, straight from the bag, once watered, the soil will shrink down by half and the seeds will not have enough soil.

Follow a Planting Schedule

Group your seeds together into similar germination rates and the same hardening off schedules. For example, planting kale and peppers in the same tray would not work well. Kale is a cold weather crop, grows quickly and will be ready to harden off far before the pepper plant.

Pepper plants love warmth and need to be planted weeks after kale. Follow the directions on the back of the seed packets for planting depths, how long it takes for the seed to germinate, and how many days until harvest. The packet will also tell you whether it is better to start indoors or directly sown into the soil outside in the garden.

Once planted, label the plants with the name of the plant and the date you planted them.

Place the planted seed trays onto the shelves. Position the lights very close to the trays. Not touching, but close. Once the sprouts come up and plants begin growing you will need to adjust the lights up each week.


Keep the soil moist by gently misting the trays daily with water. I really like my multi-purpose sprayer. Once the plants are about 2 inches high, I begin water into the trays under the plants instead of on top. The water gently soaks up into the soil from underneath.

Up Pot Your plant starts

Seedlings grow quickly and may need to be up potted to a bigger size container. A great size is the 2.5 inch pot. Transplanting discourages the plant from becoming root bound.

Hardening Off the Plants

Hardening off a plant is transitioning the plants from a controlled safe environment to the outdoors. They are accustomed to your pampering and if you immediately place them outside in the direct sunlight, they will die.

Every day, over the course of a week, take your plants outside in a shaded area. Leave them for 30 minutes. Bring them in and water them if needed. Repeat daily increasing the times spent outside.

After a few days expose them to full sun, increasing the time gradually, until they can tolerate all day outside. Now, you can leave them outside. They are hardened off and ready to plant.

While you’re waiting on your plants to grow, begin thinking about your garden set up. Read a Beginner’s Guide to Gardening.

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