My Garden: Starting Seeds Indoors

In late February – early March it is time to start my seeds indoors. There are certain vegetables that if you want to plant by seed they must be started indoors. Varieties such as tomatoes, peppers, onions, perennials and some annual flowers benefit from an early start indoors.

Insufficient light is the biggest problem with starting seeds indoors. Long, tall, skinny seedlings which eventually fall over and die are the result of not enough light. Use fluorescent lights, preferable a 4-tube ballast. Tubes must be placed 1” to 2” above the seedlings. Ballasts can be hung on chains and hooked into ceiling hooks for easy adjustment as the seedlings grow. Seedlings must receive 14-16 hours of light, and 8 hours of darkness per day. My husband built me a grow table out of scrap lumber. I have two sets of grow lights which I use over my seedlings. I found a great plan online for building a grow light stand out of PVC pipe. Very clever. Click here for the directions.

Make your own seed starting mixture or purchase high quality seed starting mix that holds the moisture yet has good drainage. Seedlings must be kept moist but not soggy. If they completely dry out just once, seedlings will die. If soggy, fungal problems can occur.

Almost any container can be used to start seeds including old milk containers or egg cartons. Seed starting trays and larger pots for transplanting seedlings are available. To retain soil moisture until seed germinates, cover your container with a clear lid or wrap in clear plastic wrap. Remove the cover immediately when you see the first seedling. I save the clear containers that salad mixes or spinach come in as my growing container.

If your containers are very small and it’s not quite time to plant your seedlings outside, you may need to transfer them to larger containers to allow for proper growth. Chose a container twice the size of the original one, fill it part way with moistened soil, and carefully transplant the seedling handling only the root ball or the leaves, not the stems. Add soil to fill, and water gently.

Before moving the seeds outside you will need to ‘harden the seedlings off’ for about a week. Take the containers outside and place in a filtered sun/shade location away from harsh winds during the day, and bring them back in before evening. Gradually increase the time the seeding’s are outside until they are ready to be planted in your garden. You can also use a cold frame to transition your seedlings. I will post more about cold frames in a later post.

How do you know when to start your seeds inside? All the seeds packets indicate the optimum sowing time based on the average last spring frost date. Generally, tomatoes are sown indoors 6-8 weeks before the average last frost, peppers 8-10 weeks, onions 8-12 weeks. Flower seeds sowing time can vary from 4-12 weeks before the average last frost depending on the variety. For specific variety information, check the back of your seed packet. You also can check the new Plant Hardiness Zone Map  from the USDA which will give you an idea of what plants will thrive in your area.

Seed viability is another thing to think about before starting your seeds. If you are using seeds left over from a previous year it is a good idea to check the viability of the seeds. An easy way to do this is to take 10 seeds and place them on a dampened paper towel. Moisten the paper towel and lay it over the seeds.Place the covered seeds in a zip lock plastic bag and store in a warm, dark place such as a cupboard. Check it occasionally to make sure it is still moist. After a week check the seeds to see if any have sprouted. By using ten seeds you can convert the viability to a percentage. If all 10 seeds have sprouted you have a 100% viability. If only 6 sprouted the percentage drops to 60%. If the viability is low you may just have to plant more seeds or get a new packet of seeds.

Check my video on the seed viability test I did on some pepper and tomato seeds.