Few things are more satisfying than watching plants blossom in your personal garden after months of hard work and sharing home-grown produce with friends and family. This year I took on the challenge of growing more than one hundred different herb and vegetable varieties from seed and it has completely blown my mind how much fun and how easy it is. One of the more exciting moments has been watching my tomatoes grow from tiny seeds (shared with me last summer by a fellow gardener) to tall stout plants. Another benefit of growing your own plants from seed is gaining access to speciality or heirloom cultivars that are not available locally.
I documented my process below with some tips and tricks on growing from seed to help accelerate your gardening journey.
When to Start Plants
Depending on your growing zone, it is often necessary and helpful to start seeds indoors to give them a head start before planting outside. Farmers Almanac publishes a planting schedule based on your agriculture zone and crop type with recommended seed start dates, depending on whether you start seeds indoors or outdoors or transplant crops. You can view the calendar for your area by clicking here and entering your zip code.
Listed below are some of the tools that I use for growing plants from seed. It is not necessary to buy a lot of expensive tools but these are the ones that have worked for me.
- Potting soil ( I use Miracle Grow cocoa coir organic potting soil)
- Seed tray (I use 72 cell trays)
- Water catch tray
- Humidity dome
- Heat mat
- Digital thermometer
- Dibber (a butter knife works too)
- Grow lights (LED shop lights from Home Depot work really well)
- Water pot
Seed trays generally have holes in the bottom for water flow and need to be placed inside a water catch tray. Fill the seed trays with damp potting soil and place 1-2 seeds in each cell. Label plants for future reference (with the planting date and variety name). Place the water catch tray on the heat mat and cover the seed tray with a humidity dome. Set the heat mat temperature between 82-86 degrees. Doing this speeds up the process of seed germination. The humidity dome maintains moisture in the air and soil. (It is possible to grow seeds without a heat mat or humidity dome but I’ve had higher and faster germination rates with both.)
Once seeds germinate (sprout), remove the humidity dome and heat mat. Set the fan on low for a couple hours daily to prevent moisture build up (and the appearance of fruit flies). Set seed trays under a grow light for twelve hours per day. I use a timer to control the grow light. (Plants generally need some darkness to grow. Leaving lights on for 24 hours at a time will not speed up growth and should be avoided.)
Bottom water plants by pouring water into the tray and allowing the water to be absorbed into the soil. Bottom watering minimizes the risk of plants dampening off (or dying). The soil should be moist but not wet. Once plants have reached a healthy size (generally after 6-8 weeks for most varieties), set the seed tray outside for a few hours each day to harden off your seedlings. This final step before planting is super important to facilitate plant transition from a controlled indoor environment to the outside elements. Some plants require pinching off after the first 3-5 sets of leaves to encourage branching for fuller and bushier plants. (Refer to the tomato plant image below to see the lower branching.) Happy growing.
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Image: Sun Sugar Tomato Plant