Starting Seeds Indoors

Starting seeds indoors is relatively easy, and right about now it’s time to start thinking about your spring planting. You can use the “Seed Company” page on this website for ideas on where to order seeds and supplies,

Starting Out with Starting Seeds

You will need a well lit space and some way of keeping your seeds and tender young plants protected.

Necessary Supplies
Sterile seed-starting soil mix
Seedling trays with clear plastic covers – either purchased or repurposed

See the cord? This system is using a heat mat and grow lights.

Optional Supplies
Grow lights
Heat mat

You can purchase kits that have seedling flats and covers that fit, or get creative with clear boxes from salads or even cut open soda bottles covered with plastic wrap.

Do label what you plant because some seeds take a long time to germinate.


Fill the tray with pre-moistened seed-starting mix, not potting soil. This lightweight mix is sterile and specially formulated to encourage easy, problem-free germination. Plant the seeds according to instructions, and water the seeds in the soil, taking care not to wash them away. You don’t have to use a heat mat, but using one will result in faster germination and growth.

Light Your Seeds

Keep the seeds covered with plastic until they sprout, then hang grow lights 2 inches above the heads of the seedlings. As the plants grow, move the lights up so that they are no more than 2 inches above the plants.

See how this baby plant is leaning towards the window? Turn the pots one quarter turn every day to encourage non-leaning growth.

Moisture for Your Seeds

Give them enough but not too much to drink. Keep the seedling mix moist, but not soggy. Damping off (which looks like rotting or wilting of new seedlings) is a problem when seeds stay too wet and cold while germinating. When plants have three sets of leaves, you can transplant to a 4-inch pot.


When you pot your tiny seedlings into the next size pot – skip the whole peat pot thing. I have never found those to work here. Likewise the paper pots so beloved of permaculture. Our air has LOW humidity and these products do not decay in a timely fashion and will stunt your plants growth.

I have tried peat pots a number of times. Plants just seem to do better once transplanted if I use plastic pots.

Planting Transplants Outdoors

Once they are hardened off (see below) you can plant your plants in the garden. Plant so that the soil line of the hole and the soil line of the transplant are exactly the same. Do not plant deeper (unless they are very vigorous tomato seedlings.)

Hardening Off before Planting Out

Vegetable transplants grown inside will need to be hardened off before they’re planted outside. Even if you buy plants that were sitting outside at a garden center, it’s a good idea to harden them off before planting. For all you know, the plants were taken from the greenhouse, loaded on a truck, and brought to the garden center on the same day you bought them.

Grew too many seedlings? Many vegetables will grow in containers and jazz up your patio!

How to Harden Off Transplants

1. Place plants in a sheltered location such as a porch or patio for the day, and bring them in at night. Do this for three or four days.
2. Next, leave them outside all day and night in the protected location. Do this for about a week. Don’t forget to water while you’re doing this!
3. Finally, move the plants from the sheltered location to a more exposed location (next to the garden). Leave them there for three or four days.
4. Plant your plants in the garden early in the day, when they have ample time in sunlight to recover from the inevitable damage to their roots. If you have a cloudy day to plant in, even better.

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vegetables-soule-growMore onions and vegetable gardening in this book Southwest Fruit and Vegetable Gardening,written for Arizona, Nevada and New Mexico (Cool Springs Press).  This link is to Amazon and if you buy the book there the Horticulture Therapy non-profit Tierra del Sol Institute will get a few pennies – at no extra cost to you.

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