Bottom watering plug trays

[SEAMSFASTER]

I raise thousands of tomato (and other seedlings) indoors on homemade lights stands under flourescent lights. I've found plug trays (I use primarily 288 cell trays) to be very useful for minimizing root disturbance when potting up.

Plug trays fit neatly over standard 10-20 trays when they are empty, but when filled with damp soil, they sag badly in the middle and are very prone to cracking. I want to bottom water and have the option of keeping the plug tray in the tray holding the water, without sagging or cracking.

Spacing on my light stands is very tight, so top watering is not an option.

What I use currently is a large plastic bin which I fill with an inch or so of water. Then I move each plug tray one at a time and soak them for a couple of minutes in the water. This is a real hassle - time consuming and quite messy. The biggest problem is that every time I pick up a loaded plug tray, it wants to crack and break some more.

What I really need is a rigid or mostly rigid plastic or fiberglass tray to both support the plug tray and allow easy watering from below while leaving the tray in place on the light stand. Tray dimensions need to be 20-1/2" X 10-1/2" X 1/2", but not much bigger in any dimension.

And the trays need to be cost effective - I've looked at dietary trays, market trays, display trays, etc., but they all cost way too much and finding the right size is difficult.

I've tried cutting off the top half of a 1020 tray. This leaves a rather flimsy watering tray which is too tight against the plug tray to do much good. Alternatively, I can arrange it so that one row and one column of cells hang outside the bottom tray. But that presents another hassle.

Another trick I've tried is placing a couple of small blocks of wood inside the standard 1020 trays and under the plug trays to prevent sagging. This works reasonably well, but having the plug tray sit on top of the 1020 tray leaves no gap for air circulation and makes watering a bit of a challenge.

Any suggestions on products, vendors, or other ideas?

[KarenO]

if you can find some inexpensive trays just the right depth etc,perhaps you could cut your plug tray to size. sort of the opposite to what you have tried? just a suggestion: find the perfect tray and cut your plug flats to fit the trays.
KO

[Hotwired]

I'm using 96 cell trays, and remove one of the cells so I can add water without lifting up the end of the multi-cell or moving the tray. I loose a square inch of cells (in my case one cell). You'd loose 4 cells per tray, but you wouldn't be dragging heavy trays around and splitting the sides (been there). I saw photos of your setup - pretty impressive. I grow about 2000 plants, but I can't imagine finding room for 10,000.

[rwsacto]

I have some 10-20 trays that are "perforated" on the bottom (actually a weave pattern). I put the plugs or seedling cups in the perforated tray and set the perforated tray in a 10-20 with water. I need an extra 1/2 inch of water to properly bottom water. I keep the plugs or cups or pots in the perforated trays under the lights or in the mini greenhouse. I move one whole tray at a time.

Call a few hydroponic shops to see if they have perforated trays.

You could also perforate some standard 10-20 trays, especially after they develop leaks, and use them to hold the plugs while you bottom water.

Hope this helps,
Rick

[SEAMSFASTER]

I probably should use bigger plug trays for the larger types, but space is a premium, so 288's work best for me at this point. I do like the idea of cutting out a corner for watering!

So here's what I've come up with: cheap plastic strips set on end and placed inside a standard, unperforated 10-20 tray, which in turn goes inside a web tray. I prefer the web trays over perforated trays for added support. The plastic strip supports fit nicely between rows of plugs. And at just 15¢ additional cost per tray, it's gentle on a tight budget!



More pics at: http://delectationoftomatoes.wordpre...-season-begin/

[lakelady]

I agree with you, those trays are junk and crack or split. I've been eyeballing those Permanest Plant Trays, but they are expensive. supposedly though, they will last for up to 20 years. Might be something to invest in for the future when you can.

[greenthumbomaha]

Antoniette - Order your Permanest trays and you will be hooked. I've been using makeshift pots pans, etc . They also sell humidity grids for the bottom for a true splurge, but pebbles work too.

The place I used to work at calls those baskets daisy trays. The cut cpattern was more concentric than the one pictured above but the same function. They are free at the big box stores during the summer. Re-purposing /recycling they have large stacks. -Lisa

[Cole_Robbie]

Yeah, you have to have any size of cell tray in a web flat if you're going to move it at all. I learned that quickly. A solid plastic tray works for transport, but they're a pain to dunk in a bin for watering, because the water takes too long to drain out when you pick it up.

If you build a tray that doesn't move, it would seem like you would have to have a drain on it, otherwise the cells get waterlogged. I was planning to build a large watering tray for my greenhouse this year that is basically a big shallow wooden box lined with plastic or a pond liner and a kitchen sink drain on the bottom. It's very similar to 'flood and drain' hydroponics.

[lakelady]

Thanks Lisa, every now and then I look those up and wish hard that that garden fairy will bring me some one morning lol....

I'll see if my friend who owns a small garden center has any of those "daisy trays". Good for the deck, but not in the house. I have all sorts of makeshift trays etc. all over the place. The only thing I noticed, is that those commercial trays are not the same size always as the ones we buy as hobby growers.