Seeds not germinating

Question

I have planted a couple herbs 2 - 3 weeks ago and this is the result.

It seems the wild rocket has pretty much all come up, the others had similar number of seeds planted but not making a show.

2x basil, 1x mint, 1x sage, 1x rocket.

Its been on a windows sill, no direct sun but good light (for the UK at this time of year). Also been keeping it under a lamp when its been overly cloudy.

Are the rest a lost cause? Is this usual when growing from seeds?

How can I get the rest to either come up, or the next batch work well. The seeds are new, purchased from a seemingly reputable (20k+ good feedback) organic seller on ebay.

Answer 1

Yes, different seeds require different treatment. Some seeds require warm soil, some cool soil. Some seeds need to be covered, some cannot be covered and need light to germinate. What is the temperature of your soil? Most seeds need some soil warmth but do not need light until they have germinated, however, that is not a rule for all seeds. My first suggestion is that you will need to separate the seeds into like-germination types and sow the seeds or at least the types separately. Additionally, sowing seeds separately allows you to move them into a stronger light after germination (which would prematurely dry the soil prior to germination) to allow for proper growth and to eliminate legginess like that of your wild rocket seedlings in the photograph.

Mint requires light to germinate. If you buried the seeds or even covered them lightly, they might not germinate. Likes soil temp approx 70°F/20-22C°. Mints also generally do not transplant very well, and do better direct seeded into the garden or pot where they will remain.

Rosemary likes warm soil, aim for 70-75°F/21-24C°. However, they will generally not germinate until they have gone through a winter season. Fake winter (cold stratify) by putting seeds in covered moist planting medium in refrigerator at least 4 to 6 weeks or freezing the seed for 3-5 days before sowing. Cover seeds lightly in rich soil, darkness will help in germination, however, germination is normally low and growth of seedlings is slow.

Sage likes soil temp approx 65-70°F/18-21C°. Germination approx 15 days. Cold stratify before sowing like Rosemary above. Cover seeds lightly/Pat down into light/well-drained soil. Darkness will help in germination.

Cilantro (Corriander) likes soil temp approx 60°F/15-17C°. Germination in approx 10-12 days. Cover seeds lightly after sowing. Darkness will help germination. Direct seeding is suggested, into light well draining soil, as cilantro/corriander does not transplant well.

Basil likes soil temp approx 70°F/20-22C°. Cover seeds lightly/Pat down into soil. Germination approx 10 days.

Wild Rocket (Arugula) likes soil temperature 65-20°F/18-22C°. I have not personally grown this, but found this study on wild rocket germination from Seed germination behaviour of Diplotaxis tenuifolia(pdf)

The seed germination increased under daylight conditions reaching a level of 80 percent but decreased in dark and continuous light. A remarkable increase was recorded (60%) in the germination of seeds subjected to +4°C shock for a week or two before left for germination. Pre-hydration followed by re-drying increased the germination to some extent (28%). These findings reveal that the storage conditions are important for establishing a seed bank of D. tenuifolia, in order to get highest germination.

Did your seed packets come with planting instructions? Most reputable seed companies will provide you with good guidelines for their seeds. See Garden Medicinals Herb Planting Instructions

Answer 2

Different seeds take different amounts of time to come up. Also, some of the seeds you planted may require more warmth than you are providing - the basil, for example.

I'd put the containers in a warmer spot if possible, and give them more light as well for the sprouts you already have (as you can see, your rocket is not getting enough light, that is why it is so long in the stem) This can be a fluorescent light placed just a few inches above the seed flats and on for 12-14 hours a day if you don't have good light in your windows. If you don't see any new growth within the next couple of weeks, then the seeds may have not been good (not likely if bought from a reputable source, but it does occasionally happen) or they may have rotted in the moist cool soil before they could sprout.