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Soil blocker vs seed trays: cubes or plastic cells

Updated: October 2026

You already own cell trays and you are asking whether a handheld press is worth the wet mix and the extra watering. Soil blocker vs seed trays is a method split, not a brand shoot-out. A blocker replaces the plastic cell with a free-standing compost cube. It does not replace the tray, and it asks more of watering than a module that holds a plug. Prices for the seven tools stay on the [Soil blocker comparison](/hub/fertiliser-soil-and-bark-mulch/soil-blocker). The Products Compared editorial team compared public UK advice with these amazon.co.uk listings. Nobody here ran a yield trial. A qualifying purchase can earn a commission at no extra cost to you.

You already own cell trays and you are asking whether a handheld press is worth the wet mix and the extra watering. Soil blocker vs seed trays is a method split, not a brand shoot-out.

Our top picks

nanovi Nanovi 4-cell 2 inch soil blocker

Best overall

nanovi Nanovi 4-cell 2 inch soil blocker
8.8/10about £30.55
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QWORK QWORK 4-cell 2 inch soil blocker

Best value

QWORK QWORK 4-cell 2 inch soil blocker
8.6/10about £19.98
View offer
Lyreh Lyreh 20-cell 3/4 inch soil blocker

Alternative

Lyreh Lyreh 20-cell 3/4 inch soil blocker
6.0/10about £28.99
View offer
On this page
  1. 1.What actually changes
  2. 2.Roots and transplanting
  3. 3.Time, water and cost
  4. 4.Paper pots and toilet rolls

What actually changes

A module is a sheet of plastic cells. You fill, tap, and sow, and the plug stays in its wall until you push it out. A soil blocker squeezes wet compost into cubes on the same kind of watertight tray. The RHS plastic-free note names soil blocks as a swap for modules, alongside paper potters and toilet-roll inners. The RHS indoor-sowing page still treats modules as the default, with pricking out after two leaf pairs. Both can be true: blocks cut plastic, and most UK households still sow in modules. You stop buying the cell and keep the tray. A module takes compost at potting damp. A blocker needs a sieved, wetter mix and two or three charges, so it is slower. The tray must be watertight for a 10-15 minute bath. Named presses sit on the best soil blocker page.

Roots and transplanting

Air pruning is the claim that sells blockers. Root tips hit the cube face and stop, instead of circling a cell wall. You plant the whole cube. The RHS says blocks help you avoid pot-bound plants and that they need more frequent watering. That pair is the honest one. It is not a guarantee of higher germination or zero transplant shock. A module plug circles if you leave it too long. You still get a plant. A 20 mm cube left under tomatoes is the wrong pot, as the Lyreh UK review says. A 50 mm cube left until it is a hard pale brick is the same mistake in a larger size. Set a sound cube level with the new mix. If it crumbles, you have made more disturbance than a firm plug. Practise on lettuce. The charge and the bath sit on how to use a soil blocker.
nanovi Nanovi 4-cell 2 inch soil blocker

Testsieger

nanovi Nanovi 4-cell 2 inch soil blocker
8.8/10about £30.55
View offer

Time, water and cost

A 24-cell module is one scoop and a strike-off. A press means a wet trug, a sieve, two charges, a scrape, and four cubes, or twenty tiny ones. In March the module wins on minutes. The press wins when you want no extra cell plastic. Blocks dry on every face, so the RHS line is more frequent watering: a pale-grey check, a 10-15 minute bath, then an empty tray. A snapping ABS press does not save that labour. DONGKER's UK file lasted three attempts. Steel prices here are QWORK £19.98, Transplant £21.00, Moendergo £27.99, and nanovi £30.55, with official Mini 4 from £31.50 just above. The press is extra on top of trays you own. It pays back only if you would have bought more cells. Iron at £76.09 with no reviews is the wrong test. One failed tray is tuition.

Paper pots and toilet rolls

Paper pots and toilet-roll inners are the other RHS swaps. A long root has more depth in a tube than in a 5 cm block. Paper can tear if it dries. Tubes collapse in a long bath. Stay on modules for a rushed sowing, a deep cell, or a tray you will not check daily. Add a 50 mm steel press only for crops you transplant as a whole cube. Do not throw the trays away on day one.

Common questions

Do I still need a seed tray if I buy a blocker?
Yes. Cubes stand on a watertight tray with a gap so you can bottom-water. The press replaces the plastic cell, not the tray. Kit trays are optional. Any flat tray that holds a 10-15 minute bath will do.
Is air pruning better than a module plug?
It is different. Tips stop at the cube face instead of circling a wall, and the RHS notes that blocks need more frequent watering. That is not a proof of higher germination or zero transplant shock, and a crumbled cube is worse than a firm plug.
Which is faster to fill?
A module tray. A blocker needs a wet, sieved mix and two or three charges per set of cubes. The press wins on cell plastic, not on minutes in March.
What about paper pots or toilet rolls?
They are the other plastic-free swap on the RHS list, and they give more depth than a 50 mm cube for peas, beans, and similar roots. They still need a tray. They tear or collapse if you let them dry or sit in a bath too long.
Can I keep my old plastic trays and just change the cells?
Yes. That is the usual switch. Sit cubes in the trays you already own. Throwing the trays away makes watering harder and is not required for the method.
Which crops stay in modules?
Deep-rooted sowings that want a long cell, anything you need to fill in a hurry, and trays you will not check daily. Tomatoes can go in a 50 mm cube. They should not live in a 20 mm mini as the only pot.
Does a press save money in year one?
Only if you would have bought more cells, or you value the plastic cut more than the time. Entry steel is about £17-£31 in this set, on top of trays you already own. A failed first tray and a return to modules means you spent the money and kept the cells.

Related pages

Soil blocker buying guide

Soil blocker

Best soil blocker UK: the top pick and best-value pick

How to use a soil blocker so the cubes do not crumble

Peat-free soil blocking: how to stop cubes crumbling

Sources

Public UK and maker sources from the research digest, used for this page in October 2026. Prices, stars and review counts are from the seven amazon.co.uk listings in this set. A German review line is not a UK sample. Ladbrooke prices are market context from the maker's site. A nationwide shop ban on peat compost has not been enacted.

  1. RHS, how to garden without plastic (retrieved October 2026)
  2. RHS, peat-free compost for seeds and cuttings (retrieved October 2026)
  3. Ladbrooke soil blocker hand tools (retrieved October 2026)
  4. Garden UK, soil blocking in the UK (retrieved October 2026)
  5. GOV.UK, General Product Safety Regulations 2005 (retrieved October 2026)
  6. GOV.UK, product safety advice for businesses (retrieved October 2026)
  7. Blackberry Lane, soil blocker notes (retrieved October 2026)
  8. Consumer Rights Act 2015 (retrieved October 2026)