Independent comparisons. We may earn from shop links. More info

Greenhouse irrigation system: water the compost first

Updated: 23 October 2026

The greenhouse is hot by late morning, and you cannot carry a can on every workday. A greenhouse irrigation system for that house should put water on the compost and leave the leaves dry. Mist is a separate job for seedlings or a short cooling burst. The tap is often outside the door, so part of the printed length is spent on the path. Prices stay on the [irrigation system comparison](/hub/garden-watering/irrigation-system). The outlet choice is on [drip irrigation or mist spray](/hub/garden-watering/irrigation-system/sub/irrigation-system-drip-or-mist). Peter F. used the 19 October 2026 listings and RHS guidance. A qualifying purchase can earn us a commission at no extra cost to you.

The greenhouse is hot by late morning, and you cannot carry a can on every workday. A greenhouse irrigation system for that house should put water on the compost and leave the leaves dry.

Our top picks

Suyeah Suyeah 49.21 ft irrigation kit

Best overall

Suyeah Suyeah 49.21 ft irrigation kit
9.2/10about £15.99
View offer
Forever Speed Forever Speed 315-piece kit

Alternative

Forever Speed Forever Speed 315-piece kit
8.2/10about £35.99
View offer
LYMIN LYMIN 240 ft irrigation kit

Best value

LYMIN LYMIN 240 ft irrigation kit
6.3/10about £24.99
View offer
On this page
  1. 1.What the greenhouse is asking for
  2. 2.Length from the outdoor tap
  3. 3.What these kits’ reviews say about tunnels
  4. 4.Timer, butt and ban

What the greenhouse is asking for

The Royal Horticultural Society tells greenhouse vegetable growers to check watering daily or to irrigate, and to ventilate. Uneven watering is one condition linked with blossom end rot in tomatoes. That is a risk about the crop, not a promise that any kit here prevents it. Drip, in the RHS notes, delivers to the root zone. About 2 litres per hour is their general illustration, not a measured output for these nozzles. Greenhouse Stores makes the same point for a closed house: water the compost, and treat overhead mist as propagation. Wet foliage in still air is how disease gets a hold. Suyeah’s style field says atomisation, so that kit is already mist even when the title says drip. Fruiting plants and seedlings do not have to share one pipe.

Length from the outdoor tap

Measure from the outside tap, through the door, and along the bench. About 15 m, Suyeah’s 49.21 ft, can lose 8 m on the path and leave a short remainder for the bench. The listing length is all of the plastic, including the path. A two-diameter kit helps only if the wide section covers that path. Forever Speed has 15 m of wider 8/12 and 60 m of thin 4/7. If the door is 15 m away, the wide pipe ends at the threshold. LYMIN and Elderoaki are about 12 m of 1/2 inch plus about 60 m of 1/4 inch. Those splits are on the drip irrigation kit buying guide. If the wide section is already short at the door, follow the how to set up a drip irrigation kit page only after you change the layout.
Suyeah Suyeah 49.21 ft irrigation kit

Testsieger

Suyeah Suyeah 49.21 ft irrigation kit
9.2/10about £15.99
View offer

What these kits’ reviews say about tunnels

UK comments in this set mention greenhouses and tunnels. They are buyer notes, not a grow-off. Suyeah’s comments include greenhouse and polytunnel use, which fits a short mist kit when the tap is close. It is a weak match when tomato leaves should stay dry. Read them beside the atomisation field. Forever Speed’s reviews mention tomatoes and cucumbers, and also the short wide pipe, so a long path is still a problem at £35.99. Kalolary is £15.99 with 3.9 from five reviews, atomisation, and about 33 ft of 1/2 inch plus 100 ft of 1/4 inch. Five reviews are a thin basis for a tomato house. Pipihome, at £29.99 and 4.6 from 43 reviews, draws comments about easy joints. A brass head is not proof of root watering.

Timer, butt and ban

None of these ten kits include a timer. Add a separate clock only after water has reached the last pot with the tap opened by hand. The RHS line about checking daily still stands. A timer repeats a dry end if that is what the manual test showed. A water butt is a poor direct feed. The RHS says it needs a pump before it can supply hose pressure. Which? recorded about 200 to 600 ml per dripper per day on solar butt kits. Elderoaki’s Solar Powered field is not a panel in the box. A greenhouse on the mains is still a hosepipe use when the live ban says so. Southern Water’s July 2025 notice names dripper hoses and automatic irrigation with hosepipes. Glass and mist do not write an exemption. South West Water leaves a water butt outside the mains ban. Check the notice, then take the pipe off the tap before frost.

Common questions

Should tomatoes be on drippers or misters?
Water tomatoes at the compost and leave the leaves dry. The RHS links uneven watering with a higher risk of blossom end rot. That is a reason for a steady root supply, not a claim that a kit cures it. Overhead mist suits propagation more than cropping. Keep any mist on a different line from the fruiting row.
Is mist useful for seedlings in the same house?
Mist suits seed trays and a short damping-down while seedlings are small. Greenhouse Stores treats that pattern as propagation, not as a way to water roots. Run it on its own zone so a mist head does not starve a dripper. Suyeah’s atomisation style is already this outlet. Move potted tomatoes onto a drip layout.
How do I allow for the path from the outdoor tap?
Add the path to the bench and compare that total with the supply coil. Eight metres of path and six metres of bench use most of a 15 m kit. Forever Speed’s wider tube is 15 m, so a door at that distance leaves the thin 4/7 coil indoors. LYMIN’s wider section is about 12 m. If the tap is further than the wide coil, the kit is already short.
Can one kit do both the tunnel and the border?
Only if you have measured both routes and each has its own branch with few outlets. A single tee off a thin coil, shared by a tunnel and a border, is how one side stays dry. These kits do not include a zoned controller. If either route is longer than the wide pipe, solve the length first.
Will a water butt feed these kits?
Not as a stand-in for the outside tap. The RHS says a butt needs a pump before it can give hose pressure. Which? saw about 200 to 600 ml per dripper per day from solar butt kits, far less than an open tap. Elderoaki’s solar wording is not a panel in the box. A pump over 12 litres per minute, or a fertiliser injector, needs a plumber.

Related pages

Best drip irrigation kit in this set

Irrigation system

Drip irrigation kit: what to check before you order

Drip irrigation or mist spray: which outlet to use

How to set up a drip irrigation kit before the timer

Sources

Public UK sources and amazon.co.uk listing fields. Listings in this comparison are dated 19 October 2026.

  1. Water Supply (Water Fittings) Regulations 1999, regulation 5 (retrieved 19.10.2026)
  2. Water Industry Act 1991, section 76 (retrieved 19.10.2026)
  3. Southern Water temporary use ban public notice, July 2025 (retrieved 19.10.2026)
  4. South West Water hosepipe ban exceptions (retrieved 19.10.2026)
  5. RHS garden watering methods (retrieved 19.10.2026)
  6. RHS collecting, storing and using rainwater (retrieved 19.10.2026)
  7. Which? garden irrigation systems (retrieved 19.10.2026)
  8. Water Irrigation micro-drip install note (retrieved 19.10.2026)
  9. WaterRegsUK hose union taps (retrieved 19.10.2026)