How to Grow from Seeds

I am often asked how to grow from seeds? So I thought it would be useful to provide this 10 step guide with links to more information for those wishing to learn more about growing your own plant’s from seed.

Raising plants from seed is one of the most rewarding elements of gardening, commercial horticulture has made plants readily available so the need to grow from seed is minimal. However, for those of us looking to raise a large number of plants on a budget or looking to locate particular plants, growing from seed can be extremely lucrative.

Once you have selected your seed source, it is time to consider the container, the best compost mix for seed starting, and the perfect location, these are all decisions that will affect the final outcome of your seed sowing adventure.

How to Grow from Seeds 10 easy-to-follow steps.

1. Select a container.

Seed-starting containers must be clean,  (use a mild bleach dip to sterilize) measure 2-3” in-depth, and have adequate drainage holes. They can be made from plastic, cell packs, peat pots, plastic flats.  You can also buy seed-starting kits, jiffy plugs, and pots made of compressed cardboard, do not invest a lot of money and recycle when possible, you will find my top tips for propagation supplies helpful. 

Remember when learning how to grow from seed the smaller the pot the sooner you will need to transplant seedlings into the next size pots, this needs to be completed once they have developed a set of true leaves. I like to use 4-5” square pots as they save space and can hold a lot of young seedlings, this way you have enough space for several species from seed.

2. Start with quality seed starting compost.

Sow seeds in the sterile, seed-starting mix or potting soil available in nurseries and garden centers. Don’t use garden soil,  or loam it’s too heavy for seeds, often containing weed seeds, and possibly, disease organisms. Soak the soil mix with lukewarm water before filling pots.

3. Seeds need different light levels to germinate.

Some fine seeds, like Aquilegia and Papaver, should rest on the soil surface but still be in good contact with moist soil. Gentle tamping after sowing will help.  Larger seeds like Lupin and Calendula should be covered with fine compost or perlite up to a depth of 3 times the seed size. After planting your seeds, use a spray bottle to moisten the soil again. many seeds will germinate in a few days or weeks, others require a cold spell or breakdown of the hard seed shell prior to break dormancy. Moist stratification and hot water methods for breaking seed dormancy are necessary for starting seeds indoors without a winters season.

4. Keep moist but do not overwater.

Under and overwatering can kill seedlings fast, so it is critical that you regulate a watering regime to avoid losses. Placing the pot in a shallow tray holding clean water will allow the compost to absorb the water it needs without overwatering. Let the pots sit in the shallow tray for approx 30 minutes and then remove so excess water can drain freely. Repeat as necessary and learn how to water and the signs that indicate a plant needs water.

5. Maintain consistent moisture.

Prior to germination, cover your container to help trap moisture inside. Seed-starting kits typically come with a plastic cover. You can also use a plastic bag, but it should be supported so it doesn’t lay flat on the soil. Remove covers as soon as seeds sprout. Once seedlings are growing, reduce watering so soil partially drys, but don’t let them wilt.

6. Soil temperature.

Most seeds will germinate at 75- 78°F. Heat mats can be of benefit for germinating seeds, the mat helps keep the soil at a constant temperature. Placing seed trays on top of a radiator other warm appliances until seeds sprout can also encourage germination. After germination, keep the air temperature just below 70°F. Seedlings can withstand air temperature as low as 50°F with a soil temperature between 65-70°F.

7. When to feed.

Start feeding your seedlings after they develop their second set of true leaves, water with a half-strength liquid fertilizer weekly.  After four weeks, or as the seeds begin to establish apply full-strength liquid fertilizer every other week until transferring plants outdoors.

8. Give seedlings enough light.

Seedlings need 14-16 hours of direct light per day for the healthiest growth. If seedlings lean toward the window, they are not getting enough light. Turning the seedling pots will help but is often not enough – you may need to add LED lighting to supplement low light levels.  

9. Improve airflow for stronger plants

Moving the air around helps prevents disease and encourages the development of strong stems. Operating a gentle fan near seedlings to increase airflow will help them grow but do not point directly at the young seedlings.

10. Climatizing to outdoor temperatures.

As seedlings grow you are going to need to move them outdoors, they need to adapt to their new environment, give the seedlings a few hours outdoors every day in partial shade will help them adjust this is called hardening off of plants.

Perennials will require some aftercare, including cut back the top growth to ground-level every late February, with the leaves and stems intact to protect the plant’s root system, to provide habitat for wildlife and bugs. The division will need to take place every 3-5 years and can be identified when the center of the plant has lost its vigor and all the healthy plant material surrounds it. How to propagate by division and renew your plant’s vigor.

I find growing plants from seed incredibly rewarding, even the smallest of outdoor garden areas can be a productive workout for all the family. Try thinking of your garden as a living kitchen and grow to love fresh flowers, organic fruit, and vegetables straight from your own backyard oasis.

Stephen Pryce-Lea

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