Monty’s guide to sowing seeds
The joy of growing plants is so much greater when they’ve been nurtured from seed. Here, Monty shares his tips to ensure a home-sown summer bounty
There is little else as satisfying in life – let alone in the garden – as seeing a beautiful plant in full flower or harvest that you have nurtured from seed
Ilove the fact that the past year’s enforced confinement to our gardens has resulted in so many people growing plants from seed for the first time. All the reports back from this front have the same tone – one of celebration at the elemental magic of the delicate little seedlings, emerging through soil or compost. I know that for many, used to buying their plants individually, half grown or even fully formed, it is a revelation that plants can be created in such quantities and with such ease and that the process of nurturing them through from that first sprinkle of seed to a young plant ready to go out into its allotted place in the garden is as enjoyable as any other aspect of gardening.
I sow seeds practically all the year round, albeit very few in November or December, but now is peak seed sowing time. The soil is warming up, the days are getting longer and light is often as important a factor in the germination of seeds and development of seedlings as heat – and April sown seeds will be ready for planting out and performing just as summer begins.
The first point about seed sowing is that it is easy. Seeds know what to do and need very little help from you or me in doing it. All we can do is give them the best opportunity to do what they do best. So do not obsess over the niceties of seed sowing.
Having said that I obsess over them like mad – but that is because I enjoy the rituals of seed sowing in themselves – regardless of what the seeds are. I love mixing up my own special recipe of seed compost, love filling the seed tray just so and gently tamping it level with the wooden tamper made to exactly fit the seed tray. I love the gentle slipping of seeds from my palm into the surface of the compost, pressing them gently down again to ensure really good contact, and then selecting the right sieve from the dozen or so second hand ones I have accumulated from junk shops and sales over the years, and gently covering the seeds with a layer of sieved compost or vermiculite and then taking them to the propagating bench, watering them and ticking a mental box of another batch sown. This is seed fetish, seed sacraments and seed ceremony as much as horticulture – and I adore every aspect of it. But it is not really necessary. Get some peat-free compost, sieve it if possible but if not take out the biggest lumps, scatter seed, cover, water, put somewhere warm and they will grow. Job done.
But there is a middle way. The older I get the more I realise that good gardening is as much about detail and timing as anything
This is seed fetish, seed sacraments and seed ceremony as much as horticulture – and I adore every aspect of it
else and that the difference between success and failure often hangs upon very fine margins. So, for what it is worth, here are my secrets of seed success.
Use fresh seed wherever possible. Some seeds – notably brassicas – stay viable for years and others, such as poppies, field bindweed or docks, have evolved to stay dormant for scores, even hundreds, of years until triggered into germination by exposure to light. But by and large fresh seed that is not more than two years old – preferably one – is more likely to germinate and grow than old seed.
Few seeds, or seedlings, like sitting in cold wet soil or compost. Your compost does not need high fertility because the seedlings are not going to be in it for very long, but it does need an open, loose structure. A proprietary peat-free (it needs repeating – never use peat in the garden for any reason) compost can be hugely improved for seed sowing with the addition of some vermiculite, grit and/or leaf mould. In fact all the leaf mould that we make at Longmeadow becomes part of our seed compost mix. Finally, I add some garden soil and garden compost to the mix to include the bacteria that is in the soil so that a symbiotic relationship between the seedlings’ roots and the soil that the mature plant will eventually grow in, is established from the very outset.
Space and light
Sow thinly. Ideally every seedling would have at least a square inch to itself spaced evenly and equally across the growing medium. With tiny seeds that is all but impossible, but it is worth taking trouble over this, not least because you will only end up throwing away half the emerging seedlings if they are too close together. The main reason is so that each seedling has room to develop good roots with minimal competition. Larger, heavier seeds such as beetroot or French beans are best sown into modules or small pots as these will then be transplanted directly to the garden. Occasionally I sow in clusters in modules – this works well for beetroot, rocket or other leafy greens – and only thin each cluster lightly, transplanting them outside in small clumps rather than as individual plants. But on the whole my aim from the outset is to produce strong individual seedlings able to withstand all the affronts that life in the garden will accost them with.
Cover the seeds both to give them darkness but also to stop fine seeds being pushed to the edges of the container when you water. Some seeds, such as achillea, celery, petunias and tobacco plants need light for germination and are best left uncovered (although often enough light
will penetrate a fine layer of vermiculite or compost). Others such as centaurea, calendula or delphiniums need darkness.
Water thoroughly but not too much. I water mine once a day in the morning and give maximum light as soon as the seedlings emerge. If you only have a windowsill then turn regularly so the seedlings get equal and even light.
I recommend buying a propagator of some kind, even if it’s only a clear cover on a seed tray. If it’s heated, even better. My propagating bench paid for itself within a few years. Heated mats are not too expensive and make all the difference. Gentle bottom heat is the key; a radiator might blast out air that’s too hot and dry.
The secret of growing plants from seed is as much timing as anything else. So prick out the seedlings as soon as ‘true’ leaves appear. This is the indicator that roots are forming so the seedling is now independent of the seed and the sooner it gets into better soil and with more room, the better it will grow. If you need to pot these seedlings on again before planting out – and this might be as much to do with the weather or even available space in the garden as the state of the seedling – then do so when the seedling has a good root system before it’s potbound in anyway. Having potted it on, allow it to grow in its new container for at least two weeks before planting out so that a new rootball forms. This will make the transfer to the soil more successful. If that sounds a little precise and pernickety, don’t be fazed by it. I try and pot on as few things as possible and go from seed tray to plug and plug to garden.
Finally, resist any temptation to feed young seedlings. There is a great temptation to mollycoddle them, especially early in spring. This is always a mistake. As soon as they germinate get them off any kind of bottom heat and stand them with plenty of ventilation. Water regularly but not too much. I never feed seedlings. The compost mixes should be more than sufficient and
I want them to adapt to the soil when planted out as quickly and easily as possible. Over-fed, over protected plants simply will not do as well as those that are reared hard. A healthy plant is one that takes all available nutrients from the soil – and if these are running low then it is time to pot them on or plant them out.
What garden plants are best grown from seed? Almost all vegetables. The only veg I’ve never grown from seed is asparagus. Many herbs, including shrubby ones like rosemary, sage and thyme, and annuals like parsley, dill or coriander grow very well from seed and give you a chance to raise plants in the kind of quantity that would otherwise be very expensive.
All annuals, tender and hardy are best raised from seed. I always grow a range of sunflowers, zinnias, tithonia, leonotis, marigolds, cosmos and tobacco plants. These can be protected as they grow, then hardened off and planted out towards the end of May or even in mid-June and will go on flowering till October frosts. Also, climbers, such as cobaea, eccremocarpus, Spanish Flag and sweet peas; though the latter are best sown in autumn or early spring. Biennials such as foxgloves, wallflowers, sweet rocket, teasels and evening primrose can be sown from May and they will germinate, develop roots and leaves this year and then flower next spring and summer. Fruit is more tricky and slower but strawberries of all kinds are easy to raise from seed. I grow wild strawberries from seed and then plant them out under hedgerows where they self-seed.
Many perennials are easy to raise from seed with a little patience. Sow now and although they’ll appear small for the first few months, they will be garden-worthy by next spring. Many grasses, can be sown and the tiny wispy seedlings will be clumps next year. Starting perennials by seed saves money and if you are planning a large border it makes real economic sense.
Whatever you grow there is one thing I can guarantee. You will be bitten by the seed bug. There is little else as satisfying in life – let alone in the garden – as seeing a beautiful plant in full flower or harvest that you have nurtured from seed. In that simple process is contained all the wonder and joy of gardening.
There is a great temptation to mollycoddle seedlings, especially early in spring. This is always a mistake