Seeds aren't sprouting.
March 24, 2010 4:53 AM   Subscribe

I-suck-at-gardening-filter: none of my seeds have sprouted. It's been two weeks. What's going on?

Last year, I started seeds in normal potting soil and they shot up within a week. This year, I bought a bag of "seed starter" soil and I was required to move the location of the seeds from last year (to protect them from the new cats). Other than that, everything else is the same - same trays, misting the cups every day with water.

Nothing has sprouted, and I'm beginning to worry. They were a mix of new seeds purchased at the same time as the soil and seeds from last year. I know the seeds from last year are still viable because I planted some in a large pot of last year's soil and those have already sprouted.

Will it just take longer for the seeds in the starter soil to get going? I seem to remember something about potting soil maybe having too much nitrogen(?) for seeds, causing them to grow too fast - could that be the explanation? Maybe they're too cold? I had the tray of seeds in a window last year.

The seeds are all typical garden vegetables - a couple types of tomatoes, peppers, and some herbs.
posted by backseatpilot to Home & Garden (15 answers total)
Best answer: I'm trying this for the first time myself, and while my tomatoes sprouted in about a week on my windowsill, the pepper seeds haven't come up yet (it's been about 2 weeks now). Apparently peppers need warmth to sprout, and they can take a while (up to a month) if it isn't warm enough.
posted by ArgentCorvid at 5:05 AM on March 24, 2010

Yeah, it may be your soil temp, it has an important effect on sprouting seeds.
posted by TungstenChef at 5:07 AM on March 24, 2010

Best answer: Germination requires water and a suitable temperature, and that's about all. Soil conditions may affect the developing plant, but the soil you have is highly unlikely to be the problem.

Just misting the soil may not be enough - it's possible that you're just wetting the soil above the seeds. Check that the soil is moist all the way through - if not, stand the pots in some water until it is. Other than that, keep everything warm and be patient.
posted by le morte de bea arthur at 5:11 AM on March 24, 2010

Rather than misting the seeds, keep the little pots in some sort of enclosure until they sprout. That's what those plastic-domed 'mini greenhouses' are for -- to keep the air around the pots moist. A plastic bag, or a piece of saran wrap, or a repurposed take-out food clamshell all work just as well. Whatever enclosure you use, put it in a warm spot. If the soil was moistened before you put it in the pots, misting should be unnecessary.

As soon as the seedlings sprout, remove the pots from the enclosure and put them under lights.
posted by jon1270 at 5:51 AM on March 24, 2010

To clarify:

1. moisten the soil
2. then fill the pots
3. then plant the seeds
4. sit pots in a tray of water for about 20 minutes so the soil takes up as much water as it wants
5. place pots in enclosure, in a warm spot, and check daily.
posted by jon1270 at 5:53 AM on March 24, 2010

Response by poster: Ok, sounds like I'll add some water to the tray so it can soak up from the bottom. I had been keeping the tray on a radiator, but the cats keep knocking it off. And patience!
posted by backseatpilot at 6:47 AM on March 24, 2010

It's unlikely that you will need to soak the pots more than once, and keeping the soil really saturated will prevent germination by causing fungal diseases. I like to do an initial soak, then drain, and rely upon the dome or plastic wrap or whatever to keep moisture in. You can always mist if you think the top of the soil is drying out.

As other people have said, temperature is important. I would have thought a radiator would be too hot. In the past I've used heating pads and even an electric blanket for a large number of flats, aiming for about 80 deg F soil temperature.

I've also been really impatient, and trashed whole flats of seeds I was convinced were bad, only to look in the bucket of discarded soil mix and see those seeds (in the cold and dark, uncovered) beginning to germinate. If I had just waited one more week...
posted by werkzeuger at 6:56 AM on March 24, 2010

I had been keeping the tray on a radiator

Uh, you may have cooked the seeds. Operating radiators tend to be waaaaay too hot. Soil temp should be around 75F; not even bath water temperature. Try the top of the fridge.
posted by jon1270 at 6:58 AM on March 24, 2010

radiator may have cooked your seeds

Another possibility is that the radiator may have killed the seeds by drying them out. If a germinating seed goes really dry even for a little while, it's dead.
posted by musofire at 8:08 AM on March 24, 2010

Response by poster: I should clarify - the first set of seeds were on a towel on top of the radiator. The cats knocked it off and spilled everything, so I replanted with fresh seeds. THAT crop has been sitting on a dresser.
posted by backseatpilot at 8:22 AM on March 24, 2010

some seeds need light to germinate, and the amount of light those needs varies. . some need darkness.
posted by y6t5r4e3w2q1 at 8:54 AM on March 24, 2010

I love growing from seeds and am not half bad at it. This information is in other posts, so I am both nthing and collating.

I'd say 99% chance that it is the soil temp or moisture level. You don't say that you have any kind of mini-greenhouse going on. You need a clear plastic bag around your tray to keep the moisture in. Even just one mini-dry out will kill the seeds attempting to sprout. Sad, but true.

The other possibility is the soil temp. If the seeds are by a window, then they may be chilly. It's kind of a catch-22 since of course they need light, but not a ton to sprout. The plastic will help with soil temp regulation as well.

I don't know what kind of trays you are using. I use whatever -- dixie cups, yogurt containers, with a small square of plastic fixed to the top by a rubberband. Then you only have to adjust the water when tiny beads are not forming on the clear plastic.

Good luck~
posted by letahl at 9:43 AM on March 24, 2010

My mom heard I was starting pepper seeds in one of those little greenhouse trays in the window, and said it would take forever. Her recommendation for low-maintenance pepper-sprouting was to moisten a paper towel, lay the seeds in a little line on the towel, and fold them up so they wouldn't fall out. Then put the whole packet in a ziplock bag, and leave it sealed on top of the fridge for 2 weeks, then check it for the 3rd week, and plant the sprouts that appear (including a little square out of the paper towel if the roots are dug in). I did that, starting a batch of seeds the weekend after I started my first batch. They sprouted in exactly the same amount of time, namely about 3 weeks. The only advantage to the paper towel method is that you don't fuss over it, or water anything, just put it away and come back in 3 weeks.
posted by aimedwander at 10:31 AM on March 24, 2010

Response by poster: So is it worth trying more seeds at this point? Or should I give it some more time?
posted by backseatpilot at 11:07 AM on March 24, 2010

You've probably got more seeds in the relevant packet than you'll ever need, so why not start another set and leave the old ones as they are in case they do sprout?

Be sure you moisten the soil mixture thoroughly before putting it into the containers. Some seed starting mixtures, especially those based on peat moss, can be really difficult to moisten the first time or remoisten once they've dried out.
posted by jon1270 at 1:21 PM on March 24, 2010

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