Some plant seeds are difficult to germinate even though they are fresh and viable. This trick works particularly well for delphiniums which benefit from a cold chill before sprouting.
For more, also see gardening tips and tricks.
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The number one best tip for seed success is to read the information on the seed packet. Seed growers want you to have success with your seeds and often they provide a lot of useful information.
One commonly over-looked section is preparation of the seed before planting. While many can be directly sown, some germinate at much better rates if they receive some special treatment ahead of time.
This may include pre-chilling seeds, pre-soaking seeds in damp paper towels, gently scraping the seed coat, and/or making sure the soil is the right temperature.
You can read more about best soil temperatures for seed germination here.
Here’s my experiment with delphinium seeds to find the best germination rate.
It’s no secret that I am a delphinium fanatic. It was an infatuation with these tall lovelies that got me into gardening in the first place and they ended up being the stars of my first garden (pictured below).
To make it affordable to fill my new garden with them, I have to start the delphiniums from seed, or take basal root cuttings from existing plants in the spring.
I recently conducted an experiment to see which seed starting method yields the best germination rate. I used seeds from the same packet planted in seed starter mix under the grow lights. Just the seed preparation methods differed.
I tried these three things with the seeds
1. Straight out of the packet.
2. Chilled overnight in the freezer (with some insulation).
3. Pre-soaked between damp towels for 36 hours, stored in refrigerator.
Each set of seeds was then planted in seed starting mix as usual.
And here are the results
1. Straight out of the packet | 20% germination rate after 16 days.
2. Chilled overnight in the freezer (with some insulation) | 50% germination rate after 16 days.
3. Pre-soaked between damp towels for 36 hours. | 90% germination rate after 11 days (same on day 16).
The clear winner is…#3: Presoaking the seeds
Some seed types love pre-soaking, others do not. Delphs definitely do. If your seeds aren’t sprouting with direct sowing, you may want to try presoaking them first.
And for my garden, the more delphiniums, the better.
More Delphinium Tips
1 How to Get Delphiniums to Bloom Twice in One Season
2 Grow More Plants from Basal Root Cuttings
- You can also start new delphinium plants by taking root cuttings in the spring. It’s best to nab the roots when the shoots are just a few inches tall, before the stalks get hollow. If you miss this opportunity, you can still start plants from seed.
3 Secrets for Growing Gorgeous Delphiniums
~Melissa the Empress of Dirt ♛