Written by Brenda F., Master Gardener Volunteer in Chatham County

Have you decided you want to try growing plants from seeds this year, but have some questions? Here are some frequently asked questions about growing your garden from seed.

Do all seeds need to be started indoors? No

Root vegetable crops, such as carrots, parsnips, beets, turnips, and radishes need to be seeded directly outdoors because the transplanting process may interfere with root development. Other cool season crops that establish well when directly seeded outdoors include arugula, cilantro, lettuce, kale, and spinach. During this time of year, most warm season crops (squashes, melons, tomatoes, eggplants, peppers, etc.) need to be started indoors because they can injured or killed when temperatures are near freezing. Beans and peas are also best sown directly in the soil and not started indoors. For a reference of when different crops can be planted as seeds or transplants outdoors, refer to the NC State Extension Central North Carolina Planting Calendar for Annual Vegetables, Fruits, and Herbs.

Do I need special indoor lights? Probably.

Seeds need light to grow. If you have a warm, sheltered place to put seedlings outside during the day, like a greenhouse or cold frame, you can place the pots outside during the day and bring them in at night. If you have a southern-facing, very sunny windowsill, that may be enough light for some crops, but you will be far more successful at seed starting with artificial light. Broad spectrum grow lights are ideal, but a combination of ‘warm’ and ‘cool’ fluorescent lights can work too. If using LED lights make sure they are grow lights to ensure the output a broad light spectrum that  plants need to grow properly. Lights need to be placed directly over the pots and placed just a few inches from the soil surface. As the plants grow, you will need to be able to raise the height of the light so that it is always a few inches above the plants. Seedlings need 12-16 hours a day of light.

Image Credit: cristina.sanvito CC BY 2.0

Do I need special pots? No

You can reuse small plastic pots that other plants have arrived in, as long as you sanitize them to prevent disease. You can also use containers like yogurt cups, cottage cheese or sour cream containers, cut off milk jugs, etc. Just make sure to clean them and make holes in the bottom for excess water to easily drain out. You can use a 1:10 bleach solution (1 part bleach to 10 parts water) to sanitize your pots. Keep your pots in a tray for easier watering and transport.

Can I start seeds in garden soil? No

Seed starting and potting mixes are free of pests and diseases that can be found in garden soil. Additionally, garden soil does not drain well enough to be suitable for use in pots or containers. It is easiest to buy potting or seed starting mixes (the latter have a finer texture), but you can also make your own potting mix if interested.

When do I start my seeds? It depends.

Generally, you can start vegetable seeds indoors about six weeks before the recommended transplanting time in the Central North Carolina Planting Calendar for Annual Vegetables, Fruits, and Herbs. Some crops, like cucumbers, squashes, and okra, grow very fast and just need to be started 2-3 weeks before the recommended transplanting time, while peppers and eggplants should be started 8-10 weeks early.

How deep do I plant my seeds? It depends.

In general, larger seeds should be planted deeper than smaller seeds. Some seeds will not germinate if they are covered with soil. Refer to the seed packet to find out how deep to plant your seeds. You can push the seed into the soil or place the seed on top and sprinkle soil over the seeds. After placing your seeds, gently compact the soil with your hands so that the seeds are getting good contact with the soil.

How do I know if my seedlings are getting enough light? – Your seedlings will tell you.

If your seedlings are getting tall and leggy, they need more light. If they are stocky and look healthy, they are getting enough light.

How do I water seeds after I plant them? From the bottom.

The best way to water seeds is from the bottom. Pour water into the tray your pots are sitting in, and they will absorb the water they need up into the soil. Water added to the top of the pot can displace the seeds and soil undoing any careful planting you did. Seedlings should not be left to sit in water. Seedlings that are kept too damp can die from damping off disease. Whatever they do not absorb in a few minutes after watering should be drained off.

When can my warm season crop seedlings go outside? After you harden them off and frost is no longer a threat.

Seedlings that have been raised inside need time to adjust to outdoor conditions. This takes about 2 weeks. The first day, sit them outside in a shady, sheltered area for an hour or two. Each day, take them back outside and introduce them to more sun and wind and reduce the amount of water they are getting. By the end of the two weeks, they should be used to being in the sun for multiple hours. If you can, transplant them into your garden on a shady day and water them well. This will help them with any transplant shock. You should also check the weather to make sure there are no frosts predicted. Do not be fooled by a string of warm spring days. Make sure you are near the last average frost for your area.

Can I use the same seed packet next year? Maybe

Seeds are alive but dormant and can only remain so for so long. Some seeds can remain dormant for years and others will not. If you have old seeds, you can get an idea of how well they will germinate by placing 10 seeds on a damp paper towel and folding the towel over the seeds. Seal the paper towel in a baggie and place it in a warm sunny place. Check the seeds each day to see if they sprout. The number that does sprout gives you a rough percentage of how many of your seeds will sprout. If five sprout, only about 50% of the seeds are viable. It is recommended that if less than 8 of your seeds sprout, you may want to just buy a new package of seeds. The NC State Extension Gardener Handbook has more information on seed propagation.

More vegetable seed starting resources.

More vegetable gardening resources.