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About Our Ebb & Flow Trays & Valves
Ebb and flow trays are flood and drain trays. A pump floods the tray from a tank below, the roots drink, then a valve drains the water back. We keep 14 lines in stock. Trays run from 520 x 520mm up to 2040 x 1000mm. Alongside them sit the small parts that make the system work: lead-throughs, conical sieves, an insert sieve, plus drain and siphon valves on a 3/4 inch thread. Prices run from £3 for a tray valve to £90 for the largest tray.
A tray on its own does nothing. You need three things to grow: the tray, a valve and sieve set, and a tank with a pump. Together they flood the roots on a timer, then drain them so the compost breathes. It suits salad leaves, herbs, microgreens and propagation. The trays are moulded from UV-proof virgin plastic, so they hold up under glass and grow lights season after season. Pair them with a grow table or a grow rack, and add an irrigation kit for the tank and pump.
Why We Chose This Range
"This range is newly stocked, so I will give you the rule I work to rather than a story. Match the tray to the table or rack it sits on. A 520 x 520mm tray wants the 0.52m grow table; a 2040 x 1000mm tray wants the 2 x 1m table. Get that pairing right and the rest is easy. I steer beginners to flood and drain over hand watering for one reason. The pump and timer feed the roots evenly, so you stop drowning one corner and starving another. Start with one tray, a valve set and a small tank. Add more trays to the same tank later."
— Matt, Founder of Greenhouse Stores💡 Tip: The trays ship without lead-throughs fitted. Order the 3/4 inch lead-through and a sieve with the tray, or the drain hole stays blank when it arrives.
🔧 Matt's Setup Tip: Set the flood depth low
You do not need to flood the whole tray. Two to three centimetres of water wicks up through the pots fine. A shallow flood drains faster, uses less feed, and keeps the roots from sitting wet between cycles.
Ebb and flow tray sizes compared
| Tray size | Best for | Pairs with | From |
|---|---|---|---|
| 520 x 520mm | Microgreens, propagation, small starts | 0.52m table or rack | £32 |
| 1100 x 630mm | A tray of herbs or salad | 1.1 x 0.63m table | £45 |
| 1100 x 1000mm ⭐ Matt's Pick | Most growing room without going huge | 1.1 x 1m table or rack | £50 |
| 2040 x 630mm | A long narrow run of crops | 2 x 0.63m table | £70 |
| 2040 x 800mm | A wider bench of plants | 2 x 0.8m table | £80 |
| 2040 x 1000mm | The full bench, vertical farming | 2 x 1m table or rack | £90 |
Frequently asked questions
What is an ebb and flow tray?
It is a flat watertight tray for flood and drain growing. A pump floods it from a tank, the roots drink, then a valve drains the water back. It suits herbs, salad leaves, microgreens and propagation.
Do I need anything else with the tray?
Yes, a tray on its own does not water plants. You also need a valve and sieve set to control the drain, plus a tank and pump below. An irrigation kit bundles the tank and pump together.
What size tray should I buy?
Match it to your grow table or rack. The 520 x 520mm tray fits the 0.52m table; the 2040 x 1000mm tray fits the 2 x 1m table. Buying the pair keeps everything square and level.
What thread do the valves and sieves use?
Most fittings use a 3/4 inch thread. The lead-through, conical sieve, siphon valve and HS valve all share it, so check the thread before mixing parts from a different system.
Can I run several trays from one tank?
Yes, that is the usual setup. One tank and pump can feed a bench of trays. The larger irrigation kits come with bigger tanks and a stronger pump to match.
Are the trays safe for growing salad leaves?
Yes, the trays are moulded from UV-proof virgin plastic. They are made for edible crops like lettuce, basil and microgreens, and stand up to grow lights and greenhouse glass.
Need Help Choosing?
Call our team free on 0800 098 8877