Seeds & Germination
Growing vegetables from seed is a lot of fun. Perhaps the most exciting time gardening is when those little seedlings start to push up through the soil, full of promise of a great harvest.
But what if nothing happens? You wait in vain for those little green sprouts, but nobody shows up for the party!
Often your first thought will be that the seed was no good, but in fact that is rarely true. Growers carry out careful trials to ensure that the rate of their seed germination is high, usually between 60% and 99%. Seeds stored properly have a long life, anything from one year to several decades and seed producers make sure that the seed they ship is from a recent harvest. So if you want to know why your seeds didn’t germinate, here are the things to check and consider.
Moisture for Germination
Most dry vegetable seeds can live for years without water but once sown they soak up water and begin to grow. Once they are wet they cannot go dry again and survive – they will just die and no amount of water will revive them. This happens long before any germination is visible. So once you have prepared your seed trays, pots or outdoor rows, you cannot let the soil dry. However it is not a good thing to keep giving more water all the time as this will reduce the air supply and air is also vital for germination.
So when you sow your seeds water thoroughly and then cover your pots or trays will some plastic film or a piece of glass until you see the first signs of germination. Outdoors you may need to water, but wait until the surface layer is dry before doing so.
Every seed has an optimal temperature for germination, below that temperature seeds will emerge slowly or not at all. Above that temperature they will be weak and prone to disease. 75oF is a good germination temperature for most vegetables, but for warm-weather plants like tomatoes, peppers or basil 85oF is better. You can get heating pads to place below the pots if the area you use is cold. When gardening outdoors it is best to delay sowing your vegetable seeds until soil temperatures are suitable.
Some seeds – certain kinds of lettuce for example – need light for germination. Check this before sowing and make sure those that need it get some light. This doesn’t mean you have to leave the seed uncovered although this may be a good idea for very fine seed. Enough light will penetrate a thin layer of soil to give the seeds what they need.
If you have taken care of all these things and your heirloom vegetable seeds still don’t appear, a common disease called Damping Off could be the cause. This disease, which is usually caused by a primitive fungus called Pythium, may kill seedlings once they have emerged or even while they are still below ground. So you may simply never see a seedling at all.
The key to controlling Pythium is hygiene. Never re-use old soil. Clean containers with dilute bleach before re-using them. As well, avoid over-watering and use soils that are a bit coarse – not too fine – as water will drain better from a coarser soil. If your vegetable seeds are dying after they emerge it may be too warm, or too cold, or the light levels may be too low.
Despite all these potential problems, growing vegetables is really easy and usually seeds will emerge without any problems. The key to successful gardening is to pay attention to the details and success will come naturally.