Seed Priming Tips for Vegetable Gardeners

31 January 2020, written by Barbara Pleasant

I had been a vegetable gardener for years when I discovered the difference seed priming can make with vegetable seeds that are slow or erratic sprouters. In my first try, I watched with amazement as parsnip seedlings from primed seeds popped up like little soldiers. A different technique resulted in beetroot seeds that emerged with the speed of radishes, while a third method gave me spinach seedlings less than a week after planting.

Everyone should know these tricks!

What is Seed Priming?

Seed priming involves procedures that initiate the germination process before the seeds are planted, resulting in higher germination rates and faster emergence of seedlings. For most seed priming methods, seeds are soaked in water for a few hours and then kept moist inside enclosed containers for varying time periods at room temperature.

Seeds of most vegetables don’t require priming because they are fast and enthusiastic sprouters by nature. But while tomato seeds sprout fast, peppers and aubergines benefit from seed priming to hasten germination. Here are seed priming tips for 12 vegetables that benefit from these special procedures.

12 Vegetables That Respond to Seed Priming

Beetroot seeds have thick, wrinkled seed coats that soften when “washed” in several changes of water. Place seeds in a jar, cover them with room temperature water, and drain off and replace the water every 30 minutes. After six changes of water, many of the natural germination inhibitors present in the seed coats are removed. Drain the primed beetroot seeds on paper towels overnight, and plant the next day. Primed beetroot seeds emerge in 4 to 5 days, compared to 7 to 12 days for dry seeds.

Carrot and celery seeds have immature embryos surrounded by hard seed coats, so dry-planted seeds often take two weeks to germinate. To speed things up, soak the seeds in room temperature water for 24 hours, drain on paper towels, and plant as soon as the seeds are dry enough to handle. Primed carrot seeds should be up and growing within 7 days.

Seeds for superior sweetcorn varieties have trouble germinating in cold, wet soil, and even under good conditions emergence can be slow and spotty. Priming sweetcorn seeds by soaking them in water for 12 hours can cut germination time in half while resulting in bigger, healthier seedlings. This method, called simple hydropriming, also works well with spinach.

Aubergine and pepper germination time can be cut in half by making a tea from dried marigold blossoms, and soaking seeds in it for a few hours. Then arrange the seeds on a paper towel that has been thoroughly dampened with marigold tea, and keep in an airtight container for four days. Plant immediately, and expect seedlings within 5 days. If you don’t have marigold blossoms, use plain water.

“Primed — Pre-germinated onion seeds are ready for planting within a week

Onion seeds that are soaked in water for 2 to 4 hours and then set to germinate on damp paper towels start smelling like onions after two days, and usually show white radicles starting on day 4. When planted immediately, the seeds will continue germinating and emerge as seedlings 5 to 7 days later.

Okra seeds can take two weeks to germinate unless you help them absorb water by cracking into their hard seed coats. Use a nail clipper to nick each seed on the opposite side from the little eye; you will hear the seed coat crack. Then soak the seeds in water for 24 hours. When promptly planted in warm, moist soil, primed okra seeds will be up and growing in only 5 to 7 days.

Parsley seeds sprout faster when primed with hot water. Place the seeds in a small dish, cover them with very warm (110°F/43°C) water, and let sit overnight. Pour off any seeds that float, and strain the others onto a paper towel. Keep the seeds in an airtight container on a damp paper towel, and plant when the white radicles show.

Pea seeds that are soaked in water for 24 hours will germinate faster and grow into larger, more robust seedlings compared to dry-seeded peas. When held in a moist container at room temperature, soaked seeds will fully germinate in about five days, and should be promptly planted.

Parsnip germination is hugely improved by soaking the seeds in water for 4 hours and then germinating them on damp paper towels until the radicles start to show, which often takes 5 days. When primed parsnip seeds are planted as soon as they germinate, seedlings are visible in about a week.