As of this writing, we’re roughly eleven weeks away from May 15, which is our last average frost date along the Front Range. As a rule, May 15 (May 30 if you garden at altitude) is the start of our frost-free growing season. That said, you should always be prepared to deal with the unpredictable spring weather. Some years we’ve been able to plant as early as Mother’s Day, other seasons it’s after Memorial Day. Using May 15 and the information on the back of the seed packets you’ve selected, will help determine the date you’ll want to start your seeds indoors.
Example: Peppers should be started eight to ten weeks before last spring frost. Ten weeks before May 15 is the week of March 7. Begin the process by choosing high quality, fresh seeds from local suppliers. Check the back of the seed packet. There should be a 2022 date printed on it. This is your assurance that the seed is fresh. When you open the seed packet you should find seeds that are uniform in size and color. Selecting premium seeds will give you better germination rates and stronger seedlings. Take time to read the seed packet. You’ll find valuable information regarding planting depth, spacing and days to emerge on the outside of the packet.
In addition to seeds, you’ll need containers, domes, labels and seed starting medium. When it comes to containers, plastic seed starting trays and inserts are the more traditional method for starting plants from seed. You fill the plastic cells with seed starting mix, then plant seeds in them. This method works very well, and you can choose from several different inserts. An alternative method would be to use peat-based containers. An advantage to growing in peat pots is once your seedlings are ready to be moved to the garden, peat pots can be planted directly in the ground, which reduces transplant shock. Domes help hold in moisture and warmth while your seeds are sprouting. Domes are available in two inch and seven-inch sizes. Once your seeds have sprouted and have two sets of true leaves, remove the domes to allow air circulation.
It’s important to label trays, so you’ll know the variety of seed you’ve planted. Labels are available in a wood or plastic, and they can follow your seedlings from the starting tray right into the garden. Now that you have selected your seed starting trays, inserts, and domes, pick up some seed starting mix. Use seed starter, not potting soil. Seed starter mixes are sterile and hold moisture well. You'll have much better results with seed germination. It's a good idea to moisten the seed starting medium before you sow your seed.
Heat mats keep the temperature of the seed starter consistent even as the grow room cools off in the evening. Keeping the soil at a constant temperature promotes faster germination, larger root systems and sturdier plants.
Starting plants from seed is a great way to get the variety of vegetables and tomatoes you want. Using the right seed and seed starting supplies will help insure healthier, stronger transplants when it does come to time to move your seedlings out into the garden.