Last year I posted an article about pre soaking seeds, which has turned out to be one of my most popular posts. It seems that there are quite a few people searching the internet for advice on pre-soaking seeds. Either in general, or for specific seeds. So I thought that I’d just add a bit to the article, to bring it up to date. You can find last year’s article, by clicking the link below, and should read it first, before reading this one.
The main reason that I soak seed before sowing, is to avoid wasted pot/module space. Some seeds germinate poorly, and all of the gaps in a tray mean that I have to sow extra trays to get the right amount of seedlings. For seeds that need extra warmth, it helps me to avoid running out of space in the greenhouses.
I generally only soak the larger seeds, as although it works for the smaller seeds, they stick together, and become harder to handle. I soak the seeds in a shallow dish, at the temperature that they would normally need to germinate. That’s so that I can leave part of the seed exposed to the air. If you leave the seed fully immersed in water, it can drown. You can soak them fully immersed, but only for limited periods. If you want to do it that way, look up the seed soaking times that they give for edible sprouted seeds, and use that.
If you want to try and soak smaller seeds, like tomato, aubergine, or pepper, you can spread them out on some damp tissue. When they are ready to plant, you can just tear up the tissue, and plant a piece with a seed attached. It goes without saying that you cannot let the seeds dry out, once you start them off. This can be difficult in a propagator, or on a heated bench, as the shallow water evaporates quite quickly. Check a couple of times a day.
It ‘s also important to look at the temperature. In my propagators I have thermometers to monitor the soil temperature, on the surface of the trays and modules, in order to help to set the thermostats correctly. Shallow trays like the ones that I use for soaking are closer to the heating elements, and consequently can get much warmer. It may be worth keeping a smallish propagator specifically for soaking the seeds that need warming. I have extra thermometers to monitor the temperature. If that’s not possible, rest the trays on something that is not such a good conductor of heat. The ambient temperature in the propagator may be warm enough for your seeds, without needing good contact with the heating element.
I use actively aerated compost tea to soak the seeds in. I believe that this helps germination. I can’t be sure of it, but it certainly doesn’t seem to hinder it.
I always wait until I can see roots emerging, and for some seeds, like sweetcorn, I wait until I get root and shoot development, before sowing. I then sow them into modules. As not all seed germinates at the same rate, I just add new sprouted seeds to the modules, as and when the roots appear, until they are full. One thing that this does is to give me a very good idea of how viable the seed is. I could get the same answer by sowing one seed per module, but then I lose valuable space.
Module size is important for the largest seeds, like Runner and Broad Beans. I find that if I sow the sprouted seed in a module that is quite tight for space, sometimes the seed doesn’t have enough room to unroll itself, jams against the cell wall, and then rots.
Sweetcorn seems to prefer surface sowing, so I keep the soil level an inch below the top of the module, and top it up once the shoot gets over the rim.
Finally, play about with it. If you’re very organised, try a batch of the same seed soaked and unsoaked, and compare the results, speed of germination etc.
Good Luck
Deano
Do you save your own seed or buy it in? Does it make a diffence where you buy seed from do you think?
Hi again Poppy
I started saving my own seed last year, and germination of that seed seems to be better than that of bought seed. The seed needs to be of open pollinated varieties, unless you know how to create an open pollinated variety out of F1 hybrid seed. The best sources of seed like that, is either the heritage seed library,
HERITAGE
or Real Seeds.
REAL SEEDS
All of my vegetable seeds for this year have come from Real Seeds.
This is a new project for me, and not something that I can explain really well, but the Real Seed site explains it really well.
I hope that this has been useful for you
Take Care
Deano
This year any seeds that I didn’t already have bar one (Runner Bean which they don’t seem to stock) have come from Real Seeds, the rest I will be using from the three shoe boxes full of seeds I have
Hi Poppy
I like their attitude. Any business which encourages you to eventually do without them has to be applauded. I’ve also bought some seed saving books, and I’m looking forward to expanding my own seed saving.
I too have a lot of old seeds, but I’m going to give them away.
Hope that all is going well with you.
Deano
Pingback: Soaking seeds: an experiment | Amateur Organics
Pingback: Pre Soaking Seeds update « The Sustainable Smallholding