Happy Easter, to those that celebrate it!
I wanted to say something about sowing and sharing seeds, and why this is so important in protecting the biodiversity of our gardens.
Cuttings or seeds?
When you take a cutting of a plant, the plant that grows from the cutting will be genetically the same, or a clone, of the parent plant. This makes perfect sense if one has a named cultivar, as your new plant will retain all of the characteristics of the parent that you want to see. It also makes sense if you are propagating plants which are notoriously hard to raise from seed and to produce plants which mature and so flower and fruit more quickly.
There are two major pitfalls in this kind of propagation. Firstly, it is very easy to transmit disease from one plant to another in the act of taking a cutting itself and secondly, if you have a massed planting of cloned varieties in your garden, there will be very little natural genetic resistance to disease and fluctuations in growing conditions. SO if one plant is affected it is highly likely that they all will be.
With seed propagation, each seed is genetically unique and carries all the information needed to grow a plant to maturity. When a plant is pollinated by another plant (not by itself) genetic material from male and female plants will be slightly different. The seeds that develop even in the same plant, will each vary slightly from the parent plant. They may contain some traits from previous generations, just like people!
F1 Hybrids are often really good for disease resistance, yields and uniformity, but sometimes other qualities like taste, or fragrance, can be lost and they tend to be expensive. This is because, the way they have been produced, you'll get a lot of wildly different plants by collecting and sowing their seeds. So you need to buy new seed each year.
Naturally occurring, or 'real', non-hybrid seeds from open-pollinated plants, on the other hand, allow the gardener to save seed from those plants that do best in their unique garden conditions, allowing those slight variations, that wouldn't be achieved by taking cuttings. These plants allow the average gardener to take control of the whole growing process from seed to harvest or display, as well as safeguarding natural genetic diversity. I think this is pretty empowering.
Why save your own seeds? Why not just buy them?
One can buy seed from varying sources, but the variety available of non-hybrid seed is dwindling. Because the EC Directive and the UK Seed Marketing Regulations prohibit the sale of seeds that are not on the National List in this country and because it costs a minimum of £1,390 a year to get an ornamental plant on the list, the small-scale seed producers and amateur gardeners that might have more of these old varieties available are at even more of a disadvantage to larger, more streamlined companies.
As fewer non-hybrid seeds are available, this will reduce the diversity of plants growing in our gardens, as old, open-pollinated varieties get dropped for not being as profitable. After all, why would a seed company under greater financial pressure choose to keep these seeds on, instead of the more expensive F1 Hybrids that the gardener has to buy every couple of years?
There are two ways to stop this happening.
Firstly, there is nothing to stop anyone swapping seeds from their own gardens. As long as they are not exchanging them for money. We can now use GreenPlantSwap to create, or find out about, local seed swapping events.
Collecting and storing seeds
Seeds have to be ripe before you sow them; most need to mature on the plant before you collect them (check by gently tapping the plant to see if seeds are being released naturally). Some can be removed with their stems and hung upside down in a paper bag in a dry place.
Once seeds are dry, remove as much of the seed pods/other material as possible and keep them in an airtight container in a cool dark place. If you have any silica bags you sometimes get in packaging, use them, or sprinkle some rice or lentils, or a charcoal disc to absorb any moisture in the air. Many people keep a plastic tub in the fridge. Different species also have different 'use by dates' before they lose their viability.
Before sowing, check whether you will need to break your seeds' dormancy before they will geminate; some need to be frozen, some need to be soaked or the seed coats nicked or scraped.
Direct sow, container-sow or seed tray?
If you are covering a large area, say a lawn or wild flower meadow area, or want plants that are difficult to transplant e.g.) carrots or poppies, then make sure your soil has been prepared well (adding extra grit or compost if needed) and with weeds removed twice. Then scatter your seeds as thinly as possible. Firm the soil, water it, then sow. Lightly rake the seeds in or sprinkle with a fine layer of compost. Only do this when the soil is warm enough by your observation; the old wives tale is that it's only warm enough to plant when you can comfortably sit on the bare earth with a bare bottom! Luckily those with imaginations need not actually do this (unless they want to!)
Sow seeds in containers that are a little larger and that you don't need as many of. These also include plants in the bean and pea family who don't like root disturbance; they will appreciate 'root trainer' pots you can easily open from the side. Everything else can be sown thinly in seed trays. Be aware of how many plants you need at a time versus how many you will thin out, how many seeds may not germinate and how many plants you may lose to slugs. This is a fine art that I think one can only really learn from experience, but of course it's always nice to have a few extra plants to swap...
Depth, compost, watering
Some seeds need light to germinate (e.g. foxgloves), and so don't need covering. Most need only covering to the depth of the width of the seed, so be sparing. The main thing is that the seeds have good contact with the soil, so it's good to firm down the soil before placing your seeds and then after they have been covered.
The compost that you use doesn't need to be rich, because the seed already has a store of energy to allow it to send up its first shoot and root before it can photosynthesise. In fact, too rich a compost can burn seedlings. So use seed compost, or your own mix of compost, sand and leaf mould. Make sure it it sieved finely, as Rachel suggests in her fab post about compost, not just because of the rubbish you don't want in there, but also because getting even, accurate planting depths will improve the germination rate.
Water the compost before you sow, and you won't displace your seeds. Or you can water them from below. If you're starting seeds off indoors, cover your trays or containers with clingfilm or a taped clear plastic bag to retain that moisture, but make sure you remove it once you see the shoots poking through the soil. Then when the soil is dry to the touch, you can water again with a mister or fine-rosed watering can. Direct-sown seeds only need to be watered if there is a dry period of no rain and hot sun for a couple of days. Once they emerge, water sparingly, early morning or evening, if they need it, to encourage them to develop strong roots.
Always label your seeds with the date of sowing and the full name so you don't get confused! Some plants take a long time to germinate, others might just not be germinating, for a multitude of reasons.
There is so much more to say on this subject, but this post has already got very long so I'll save it for another rainy day!