Sowing and growing in clumps
Enjoy the many benefits of sowing two or more seeds together, as opposed to a single seed per module or station.
- Grow more plants in the same area of propagating space.
- Use less compost to propagate the same number of plants.
- Save time because you are planting two or more at once.
- There is a companion effect: I observe how plants like being with their friends in clumps, they like to Grow Together (my new book appearing April 2025) See how many beetroot I grew in this small 25 cm space:
Beetroot Boston multisown 1st March, this is 25th June and is 117 days since sowing
Multisown leeks Jolant three months in the ground after potatoes – most growth is above ground so easy to harvest, and the long pale stems are sweet
Onion cover just removed, 25gsm fleece against the leaf miner, was on the onions (no hoops) 24th March to 30th May 2025
Onions resulting by 14th July are Rose de Roscoff, Long Red Florence, Red Baron
Charles with radish multisown on 3rd March, ready to transplant at 15 days
Because you can grow more plants in the same space, it’s feasible to grow more early crops of, say, turnips and radish. This is at a time when warmth for propagating is scarce and precious, in February and early March, and one multisown tray can hold over 200 plants (as above) instead of say 60, for a notable space and compost economy.
Harvests of radish and turnips in April and May are welcome as ‘hungry gap’ vegetables, when fresh food is scarce. You then have time to clear the space before planting summer beans, courgettes, brassicas etc.
In my experience, other vegetables not mentioned here make better harvests as singles. For example cabbage and lettuce to make hearts, swede and celeriac to make large roots. They do grow well in clumps, it’s more a question of the harvests you desire.
It’s easier to pick the outer leaves off single lettuce plants, then off those in groups of two or three. On the other hand, it works well to pick larger leaves off two or three salad rocket and mustard plants in a clump.
Salad rocket under mesh, transplanted a month earlier and picked once, with the mesh helping to reduce damage from flea beetles
Broad/fava beans are an exception because they ‘tiller’, making many stems from one seed, so they are best sown as single seeds. Single sown broad beans look like they were multisown.
Parsnips and carrots grow best from direct sowing, in terms of making a long, non-forked tap root. Nonetheless you can transplant them, and carrots are feasible in clumps of two to four.
Seeds in a tray for pricking out to grow as singles, while multisown veg are sown direct to modules
New transplants of multisown onions in September, with leeks planted in June from an April sowing
Multisown peas for planting in clumps, five seeds for shoots and three for pods
Tokyo Cross F1 13th October, two months since multisowing on a waning moon. These are a sweet and crisp Hakurei type of turnip, well worth growing for flavour and earliness.
My suggested numbers for great harvests
You can enjoy multisow benefits with variable seed numbers according to the size of vegetable you want. Only do not sow too many root vegetables in a clump, or you will have more leaf in proportion to root, meaning the roots will stay small.
- For medium-sized plants and high yield, the second column lists my suggestion for the number of seeds to sow, per module. This is a different number than in the third column as it allows for non germination of some seeds, and for multiple germination in the case of beetroot and chard.
- The third column lists how many plants can grow to a harvestable size in clumps.
CD60 module tray with transplants of good-sized radish multisown, while behind are singles of pricked out lettuce
Multisown turnips Tokyo Cross F1, 9 weeks since sowing, and this is quite large for a variety best eaten small
Multisown spring onions 4 weeks old and ready to transplant in clumps of 6–10
For further advice and information, have a look at my YouTube playlist, Seeds, Sowing/Multisowing and Propagation, and to learn much more about sowing in general, see my Propagation knowledge pack.
