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How and When to start Seeds Indoors

As the Spring months approach, it's important to start planning and preparing for the upcoming growing season. One crucial step in this process is starting seeds indoors, which can give your plants a head start and increase the chances of a successful harvest. In this article, we'll go over the basics of starting seeds indoors, including when to start, what seeds to choose, and how to care for them.


The best time to start seeds indoors depends on the specific plants you're growing. For most vegetable crops, it's recommended to start seeds 6-8 weeks before the last frost date in your area. In Spokane, Washington (Zone 6b), the last frost date is typically between April 15th and early May, so you should aim to start your seeds around mid-February.

Different crops do have unique germination times and can take longer or shorter to mature indoors, so make sure to read the back of your seed packets for more information. For perennials, the timing may vary (and they may require cold stratification), so it's best to check the seed packet or consult with a local nursery for specific guidance.


When choosing seeds to start indoors, it's important to select varieties that are well-suited for your growing zone. Take into account the length of the growing season in your area. In Spokane, the growing season is about 180 days. Some crops will require a longer season than you can accommodate for, so take this into account when selecting seeds. Most seed packets will have this information listed on the packaging.

Additionally, consider the amount of light and space you have available when selecting seeds, as some plants require more to grow than others. Some good options for vegetable crops to start indoors include tomato, pepper, and eggplant. For perennials, consider starting seeds of columbine, rudbeckia, and lupine, all of which have native varieties available to sow.

Some local retailers in the Spokane area we recommend to source seeds from are: Northwest Seed & Pet, Ritters Garden & Gift, and The Plant Farm.


When starting seeds indoors, it's important to use a soil mix that is specifically formulated for seed germination. These mixes are typically made with peat moss or coconut coir, which provide good water retention and drainage, as well as perlite or vermiculite, which improve aeration and drainage. Additionally, a seed starting mix should also be sterile to prevent any disease or pests from infecting the seedlings. It is unnecessary for seed starting mix to have nutrient additives or fertilizers, as the seeds will shortly be transplanted into soil that will feed them for a longer period of time.

A good quality seed-starting mix is a fine blend that holds enough moisture to keep the seeds consistently hydrated, but also has good drainage to prevent the soil from becoming waterlogged. You can make your own soil mix by mixing together equal parts of peat moss/coco coir, vermiculite and perlite. Be sure to moisten the soil mix before planting the seeds, and give them adequate lighting, warmth and moisture.


Starting seeds indoors requires proper care and attention to ensure they germinate and grow into healthy seedlings. Here are a few tips to keep in mind:

  • Provide adequate light: Most seeds need at least 6 hours of direct sunlight per day, or 12-16 hours of artificial light from grow lights. If you don't have access to a sunny window or grow lights, consider using a fluorescent light to supplement natural light.

  • Keep the soil moist: Seeds need to be kept consistently moist, but not waterlogged, to germinate properly. Use a spray bottle to mist the soil, or place a plastic cover over the seed tray to create a mini-greenhouse.

  • Monitor the temperature: Most seeds germinate best at a temperature of around 70-75 degrees Fahrenheit. Keep the seed tray in a warm location, such as a sunny windowsill or near a heat source. Many grow lights will provide an adequate amount of head for seedlings, but LED lights often do not give off much heat if any at all.

  • Transplant seedlings: Once your seedlings have grown their first set of true leaves, it will soon be time to transplant them into larger pots. Be sure to harden them off before transplanting in their final place the ground, by placing them outside in a sheltered location for increasing amounts of time over the course of a week.

Starting seeds indoors may seem daunting at first, but with a bit of planning and attention, you can give your plants a head start and increase your chances of a successful harvest. For gardeners in Zone 6b (Spokane, Washington), starting seeds in mid-February for vegetable crops and consulting with a local nursery for perennials, is a good idea. Don't forget to provide adequate light, keep the soil moist, monitor the temperature and transplant seedlings. Happy gardening!


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