A propagation tray is bought once and used many times, so the number that matters is not the price of the tray but how many cycles it survives. A flimsy tray lasts a season or two and then cracks at the cell wall, and every cracked cell is a place where the next batch can be lost to a disease carried over from the last one. A rigid tray rated for 50 steam sterilisation cycles changes that arithmetic: the tray becomes a capital item rather than a consumable, and the disease transfer between batches stops being something that gets managed. The stacking also matters once trays are bought by the hundred.
On a propagation bench the trays are the lowest cost item on the list and the one that gets replaced most often, which is exactly why the replacement rate is worth looking at rather than the unit price.
Steam sterilising trays between batches is standard practice, because a tray that carried one crop can carry its problems into the next. A tray that cannot take the heat is either not sterilised, which risks the batch, or is replaced often, which costs money and generates waste. Rigid food grade plastic rated for 50 cycles of steam sterilisation removes the choice: the same tray comes back onto the bench clean, batch after batch, until the material finally goes. Add the stacking ratio and the picture is complete, because a tray that nests flat at 100 to a carton takes about 60 per cent less storage volume than the same number of loose trays, and storage is the cost nurseries notice second only to labour.
The trays are used on propagation benches, over heat mats where the tray sits directly on the mat, and in nurseries running lettuces, herbs and flower plugs through several sowings a year. Sitting on a heat mat is a harder duty than it sounds, because the tray is warm and wet at the same time, which is exactly the condition that softens a light plastic. The drainage holes and raised ribs are what keep the cells from standing in water and the roots from rotting in the first weeks. Growers moving the same plugs on into fabric bags often take a planting bag from the same range, and where the trays sit under shade cloth, the shade net range covers that separately.
| Model | NP-004 |
| Material | Rigid food grade PVC |
| Cells | 200 cavities per sheet, each 25 mm square |
| Drainage | Drainage holes with raised ribs |
| Sterilisation | Withstands 50 cycles of steam sterilisation |
| Colour | Black, grey, blue, or customised |
| Packing | 100 trays per carton |
| Customisation | Hole size, colour and thickness to order |
The 200 cells are 25 mm square, which is a plug size that suits lettuces, herbs and flower plugs rather than anything that needs to grow on for long in the tray. The cells are tapered, so the plug lifts out without the root ball being squeezed, and that matters more than it looks: a plug that has to be levered out loses roots at the edge, and those are the roots that establish the plant. The drainage holes are paired with raised ribs so a cell cannot sit in standing water on the bench, which is the usual cause of damping off in the first fortnight. Where a larger container is wanted for the next stage, a grow bag with air pruning seams is also available.
The 200 cell tray is one of a range that also covers 28, 32, 65 and 72 cell formats, in the same 21 by 11 inch footprint, with cell sizes from 30 mm to 62 mm depending on what is being raised. Colour and wall thickness are set with the order, and hole size can be changed without a minimum order complication. Trays stack 100 to a carton. Tell us the crop, the plug size and the quantity, and we will confirm the format and the packing. Buyers tracking what is going into propagation and nursery production can follow trade coverage such as HortiDaily and FreshPlaza for what growers are installing.
How many times can the tray be sterilised?
It withstands 50 cycles of steam sterilisation without cracking, which is what makes the tray a capital item rather than a consumable. Tell us your sterilising routine and the batch turnover.
Can I change the cell size?
Yes, the cell format and hole size can be specified without a minimum order complication, and the range covers 28 to 200 cell layouts. Tell us the crop and the plug size.
Do the trays work on a heat mat?
Yes. The rigid food grade plastic does not soften when it is warm and wet, and the raised ribs keep the cells clear of standing water on the mat.
Tell us the crop, the plug size, the quantity and how the trays are sterilised, and we will confirm the format, the sample and the packing that suit your order.
Mark Wu, Co-founder & Technical Director, Sichuan Zhifang Net Industry. 15 years manufacturing agricultural nettings for growers in 32 countries.
