When to start seeds indoors

When to start seeds indoors

The first thing you need to do is to find out when the average last frost is in your area. Look up and find out what zone you are in. Then look at when the last frost is.

The zone is not essential for veggies or plants you are growing for a season. The zone is only pertinent for perennial plants but knowing the zone will tell you when the average last frost occurs. Most plants will not tolerate frost and not freezing.

Here is the zone map. You can look it up online to get a better look at it. Many seed sites will ask for your zip code and tell you what zone you’re in.

Most seed packets recommend how many weeks before the last frost you should start the seeds inside. It is hard to wait when you live in Minnesota. You want to get them started as early as you can. We want winter to be over and spring to start. Don’t start them earlier than the recommendation. If it says 6 to 8 weeks, don’t start them earlier. They will get too big, or you will need to repot them more than you need to.

A step-by-step guide to going from starting the seeds to planting in the garden.

  • Read the seed packet. See when to start indoors by the time to plant before the last frost for your location. Look at the zone map, look up your zip code, or type the last frost for the town you live in into a Google search, and it will tell you what day it is. Then work backward from there. There is plenty of time for your plants to grow, so don’t be too eager to get them in the garden early. A good thing to do is just for your information. Search for the first frost in the fall as well. Then you can determine the number of days in your growing season. For most plants, from planting to harvest is 70 days or fewer. You can see there is plenty of time to grow. It is a pain if you must cover your tender plants because of frost. Also, if the soil is not warm enough, the plants will not grow anyway, so wait a few days if it’s close to frost on your day to plant.
  • Decide what containers you will use for the type of seeds you are planting. If you are using four-inch or 6-inch pots or solo cups. Moisten the starter soil before filling the pots. Push down on the soil gently to pack it slightly. Do not pack it down hard. I have a bussing tub for clearing tables in restaurants that I use for the soil bin. Pour soil into one side of the tub and fill the starter pots on the other. This keeps you from getting dirt all over the place. I put the soil in the smaller seed starter trays dry. It is much easier to fill the cells if the soil is dry. Once you get the seed tray filled with dirt, set them in a pan of water or a sink with a couple of inches of water. Set the starter trays in the water for a couple of minutes. You can watch the water move into the soil through the clear plastic trays. Then spray the top of the soil with the sprayer after you plant the seeds.
  • Take a pencil or the tool that comes with most seed starter tray kits. Push it into the center of each cell or each bigger pot. Go by directions on the seed packet regarding how deep to plant the seeds. There are a few seeds, peas, and sunflowers that you want to soak in water overnight to soften the shell and make it easier for them to germinate.
  • Put two seeds in each hole. Gently cover the seed with soil. After you cover the seeds, spray the top of the soil with water. Spray enough to get the soil damp. Go to the next tray and repeat the process.
  • If you have a heat mat, put the trays on it and cover them with a clear dome to keep the moisture inside the tray. Most seeds require darkness to germinate. Put something over the dome to block the light. I use the black 10×20 trays upside down over the starter tray to keep them in the dark while germinating. These work well with anything you’re starting. If you have the four- or six-inch starter pots in the 10×20 trays, you just put another 10×20 tray on top flipped over to keep it dark in the pots. Most seeds require dark to germinate. All veggies that you will start inside like it dark. Some flowers need a little light to germinate, but very few. It should say that on the seed packet if they need light to germinate.

When germinating the seeds in the starter pots or solo cups, this is how to cover with the 10 x 20 trays for the dark cover.

  • Once the seeds germinate and grow, take off the dark cover but leave the clear dome on the tray for a few days to keep them moist. If you are using grow lights, set the trays, so the lights are two to three inches above the plant. Keep the dome on for a few days to help keep the plants and soil moist enough to keep growing. You want to get the plants close to the light source, so they don’t have to stretch for the light. If they are far from the light, they will stretch and get leggy, and won’t grow a thick stem. It is also a great idea to have a fan gently blowing across the plants to help them get plenty of airflow and acclimate to a bit of stress.
  • After a few days, remove the dome and let the seedlings have air and light. From this point on, bottom water the plants. The seed trays have a solid tray that sits under the seed cells. Put some water in the solid tray and let the water wick up through the soil to the plant roots. Don’t leave the seed cells sitting in water. Dump the excess water out of the seed trays. I prefer to set the cell tray in a bigger pan of water for a couple of minutes to soak up water in the soil. I like this way because I can do several at a time.
  • The first leaves you see on the plant when it comes up are called seed leaves. They are there to help the plant get started. Seed leaves look the same on most all veggies. The next leaves that come out are the true leaves. These leaves will look like the leaves on a full-grown plant. The lower leaves on the seedling are the seed leaves. The ones above are the true leaves.
  • Once they get the true leaves, thin the seedlings to one per pot. Look at the plants, see which one looks healthier, and cut the other off at the soil level. If careful, you can loosen the soil, pull one out, and plant it in a different pot. I have done this, and I don’t think it is worth the stress on the plant or the time and work it takes. You will feel you should try to save all the seedlings, but it’s not worth it. The little seedlings are much more stressed than when the plants get bigger. You also will have the roots of the two plants growing together. Trying to pull them apart can damage the sensitive roots.
  • Seedlings need lots of light. You should have a timer if you use grow lights and give your seedlings 16 hours of light per day. From this point on, you need to check the plants twice a day and water them when they need it. Do not over-water them. You should be bottom watering the plants from this point on in the starter trays. I have two of the tubs that are used for bussing tables in restaurants. I used one for a soil pan and the other for watering the starter trays. I put a couple of inches of water in the tub and sit the starter trays in the water for a couple of minutes when they need to be watered. Once you do it for a while, you can tell by the weight if they are dry or not. For the bigger plants, I usually water from the bottom and the top a little until the plants get bigger and I know the roots are getting down to the bottom. It doesn’t take long; the roots grow fast.
  • One thing that I have learned from growing microgreens is that the roots grow fast. I can start peas, and once they germinate, they send out roots that will be three or four inches long in three or four days.
  • Once the seedlings in the starter trays get to where you can see the roots are growing around the cell, you need to think about repotting them. They will get root bound if the roots circle the cell and get tangled together. When you see the roots growing out of the hole in the bottom of the starter trays, you can add water to the bottom tray. Don’t add too much. You don’t want the roots sitting in water.
  • When repotting your seedlings, plant them in the bigger pot, so the soil level on the plant stem is the same as the soil it came out of. Tomatoes and peppers, you do this differently. You can plant them deeper into the soil, and they will grow stronger roots. They will develop new roots out of the stem that is under the soil. This will make for a more robust and healthier plant. Do this as well when you plant them in your garden outside. When taking them out of the starter pot, don’t pull on the plant; push through the hole in the bottom with your finger and put the plant between your index and middle finger to support it. If you need to pull on the plant, pull from the leaves, not the stem. The seedling stems are fragile and can break easily if bent.
  • Keep checking twice daily to ensure there are no issues, and water when needed. When you get to a week before you plant the plants outside, you need to do what is called hardening them off. Up to this point, the plants have been in a close to perfect environment. When they go outside, we subject them to wind, harsh sun for long hours, sometimes heavy rain, and high humidity, depending on where they live. If you don’t harden them off, the stress can drastically slow their growth or even kill them. After you harden them off, you are ready to plant them in their last pot or bed in the ground, where they will live for the next several months.

Follow these steps and you will be successful at growing your garden and showing what you can do with a little work, and it’s fun.

Leave a Comment