The Cottage Smallholder

stumbling self sufficiency in a small space

Free planting vessels or state of the art equipment. CS is experimenting with seed germination devices.


Sweet peas and peas. April 2010

Sweet peas and peas. April 2010

As someone said on a forum – root trainers are the marmite of the horticultural world – you either love them or hate them.

I’ve been thinking about testing out root trainers out for some time. The price put me off initially and then I reckoned that if we get better sweet peas and beans I’d soon recoup the cost, especially as they are reusable.

I must admit I was a bit disappointed when they arrived. They seemed awfully flimsy. But once that are packed with compost and placed in the rack they seem quite sturdy. On another forum someone pointed out that they can be repaired easily with electrical tape. Most people who are enthusiastic about them have had them for at least five years. Only time will tell if they are just a snazzier looking version of their humble cousin – the loo roll.

They take up far less space which is a bonus. At this time of year space is at a premium. An area of an ordinary seed tray holds 32 long cells – you can get short cells but I reckon that the longer ones are a much better investment. I got my root trainers from Unwins. You can also get them here.

I decided to experiment and grow sweet peas in the root trainers and also in 5” pots to see whether the root trainers give the plants a better root system and produce stronger plants. The germination rate has been the same in the pots and the root trainers. In a month or so we’ll have a better idea how the two methods compare.

I’m also experimenting with Jiffy7 pellets (35mm). They are now available in coir rather than peat. I’ve had good results with them so far and grew quite a few hardy annuals and perennials in them over the winter. Investing in these used to seem a bit of an extravagance to me but last year I spent hours and hours pricking out and potting on seedlings. Hours that could be well spent elsewhere in the garden.

Admittedly we grow around two thousand plants a year. A lot are raised in seedbeds but quite a few need the higher temperatures of the electric propagator to germinate. The potting on of these Jiffy 7 raised seedlings will be easier with far less root damage and hopefully sturdier plants. Another benefit is that quite a few can be packed into the electric propagator and being separate units they can be whipped out immediately germination takes place. Last year I was cutting up the trays as seeds germinated and was left with rather useless chunks of cells at the end of the season. Incidentally I bought cheap green cell seed trays from QD and they were just a one season wonder – so a real waste of money. The sturdier black ones, with a bit of care, can last for several years.

I tried sowing peas in an old length of guttering the year before last. In the confined space in the green house I kept on tripping over them so last year I tried another method which worked really well. I cut 4 pint plastic milk bottles in half (from top to bottom) and threw away the handle side. The remainder made containers that are great for sowing peas in the greenhouse or polytunnel. I used multipurpose compost and put a piece of glass over the containers to speed up germination which was pretty fast. The roots of the baby peas created a mat that kept the soil intact when they were moved to grow on in a border.

I repeated the sowings at two week intervals which gave us an extended season of fresh peas and crisp raw shoots for sandwiches.  I sowed Hurst Green Shaft a delicious variety that has a long cropping season and also freezes well.

Have you tried root trainers? If so what did you think of them? Have you a patent method for germinating seeds that will grow into healthy plants? I love to know.

  Leave a reply


  1. Used them for sweet peas but not much improvement from using toilet roll tubes. I find them fiddly to fill with compost too.

    Fiona – have you seen page 42 in the Amateur Gardening mag this weeek 🙂


  2. As has been said before, coir is NOT poisonous to dogs, although there’s a chance of a bowel blockage if they’re mad enough to eat it dry. Coir is from the coconut, no relation to cocoa. Cocoa shell mulch IS poisonous to dogs, and they’re more likely to eat it as it smells of chocolate.

    Back to the topic – I first tried rootrainers a few years ago and was also disappointed by how flimsy they are. It tends to make cleaning them a chore because they will tear if not handled lightly. That said, mine are still going and they do seem to be effective. I found they didn’t improve germination but they did improve root growth. Tried both main sizes, the big ones are a bit small for sweet peas if anything, the small ones worked very well for smaller veg.

    Last year I also tried planting in toilet roll inners: cheap, but not really a success, because it was very difficult to get the moisture level right. Probably worth a go for seeds that aren’t too bothered in their starting conditions, but no good for anything fussy. The cardboard also got pretty manky – not sure if paper pots would suffer the same way.

    Paula: Haxnicks (new producers of rootrainers) will ship overseas, but I think you have to contact them directly to get a quote for the shipping.

  3. Never heard of them until reading your post although on clicking the link I did recognise the long root/soil plug pictures from somewhere.
    I am experimenting with making pots out of newspaper this yr with a wooden pot maker. It looks more like something you’d find in a kitchen for smashing up spices but I have made a few and its so easy it makes a little newspaper pot about 4cm round by about 5-8 cm tall depending on how wide you cut the strips of paper. Brilliant way to recycle newspapers and also you plant the whole thing so the roots don’t get damaged or disturbed when transplanting out of a cell..

  4. I have used root trainers for sweet peas which have worked well. When it comes to transplanting there is little root disturbance and the plants get away to a good start.

  5. skybluepinkish

    I love my root trainers and would love more but as you say they are quite pricey. I have never had much success with jiffy pellets, I don’t know why, although the cats (who like to sunbathe in the greenhouse) have a tendency to push them out of the way so I suppose that doesn’t help!

  6. I have a root trainer kit that cost me about £5. I’ve had it for at least 4 years, and it’s fine, although you will have to store it somewhere it doesn’t get knocked (the lid, particularly, is flimsy). The root training modules are great. When you are ready to plant out, lay them on a flat surface and open them out, rather than try to do it in your hands.
    I’ve grown sweet peas for years by soaking seeds overnight. I don’t nick them first, although some people do. I get 95-100% germination!

  7. Margaret Thorson

    We grow thousands of seedlings every year all in soil blocks. We mainly use the 1 1/2″ block makers but have a 2″ one for things like squash and pumpkins. No pots, no waste, easy to use. Love them.

  8. I had never heard of root trainers before but they look intriguing. I’d better not make the investment in them yet though, because I still have six pack cells from last year that I haven’t used yet! I’ll be curious to see the results of your experiment, though.

    I feel duty-bound to tell you that coir is poisonous to dogs, so don’t let you your minpins near it. I imagine that it wouldn’t take much to do in such little dogs.

    I checked on Amazon US- they don’t have root trainers!

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