Wednesday, August 3, 2011

Watering and trays…

Watering can be a huge chore if you have lots of plants. It used to be a double pain for me, because I used the styrofoam boxes made for holding vegetables. While they were cheap and did the job, they never held quite enough water to see me through the hottest months of summer. And they would always dry up just in time for the hottest day. This happened to me just after Christmas 2010. They trays were full one day, the next, I had dying Dionaea. As each tray only held 3 Sarracenia (8 if they were in 120mm pots), it also took me at least 40 minutes to make sure they were all filled. I still use some of these trays for my S. purpurea type plants, along with overflow S. flava from the greenhouse:


Fortunately, inspiration for how to get around this came from my good friend John Creevy of Gotcha! Plants in Queensland. John, who grows all his stock from seeds, has extremely large trays to house his massive collection of plants. To give you a scale of his Sarracenia collection, here is his “stock” from which he cross-pollinates and collects seeds:



John uses UV stable pond liner laid over a frame made from fence palings or small sleepers. The base is either sheet metal or level sand. While telling John how tired I was of wasting so much time filling trays, he encouraged me to make similar trays for the greenhouse. Here is a photo of the end product (for scale, the bigger pots are 200 mm/12” in diameter):

My tray

The tray is raised off the ground on treated pine 1” x 2” rails screwed to a base of marine ply. Raising the tray up helps keep it dry to maximise its life. I also drilled drainage holes in the tray base to get maximum drying effect. Here is a plan of the general design I used:

Those handy with building things should be able to make something like this reasonably easily. For those who don’t make things like this so frequently, here are step-by-step instructions based on how I made mine.

You will need:

(#1) 2 x treated pine fence palings for the long sides of the trays. The palings need to be at least 90 mm wide, 12 mm deep and cut to length b
(#2) 2 x treated pine fence palings for the short sides of the trays. They need to have the same width and depth as the long sides and also need to be cut to length a
(#3) 1 x 12 mm marine ply sheet cut to the width a and length b
(#4) 3 x 1” x 2” treated pine cut to length b (note: treated 2 x 4” or greater widths may work better if you have wet conditions or are putting the tray on soil. 2 x 4 is fine if you are putting it on gravel or concrete)

Pack of treated pine compatible screws – 30 mm long
Pack of treated pine compatible screws – 40 or 50 mm long
20 mm and 6 mm drill bits
Drill bits suitable for guiding the wood screws
Cordless electric drill
Staple gun and staples
UV stable pond liner at least 50 mm longer and wider than lengths a and b (get the thickest type of pond liner you can afford. It must specify on the packaging that it is treated to be UV stable. If it does not say UV stable, look for something else).
Plastic weed mat (preferably woven and not watertight), a roll long and wide enough to line twice the length and width of the tray you are going to make
Coarse sandpaper or good quality wood plane
Tape measure
Pencil for marking timber
Dust buster style vacuum cleaner (useful if available)

Important note – use treated pine timber or suitable rot resistant hardwoods whenever possible to maximise tray lifespan. The base can be untreated or marine ply as you will drill drainage holes anyway, and my design keeps if off the ground.

1. Measure up your growing area to determine how big you need to make your tray. In my case, the greenhouse is 1.8 x 1.8 meters (6’ x 6’) so I designed the trays to have length b of 1.7 meters and length a of 0.6 meters. In deciding what size timber you will use, also consider what size fence palings/other suitable timber you can get. I can get 1.8 and 1.5 meter palings here in Canberra from Bunnings.

2. Smooth the treated pine sleepers using either sandpaper or the wood plane. This step is important, as rough timber can burst the pond liner and ruin all your hard work. Take the time to get it right!

3. Construct the sides of the tray from the treated pine sleepers. Use the 30 mm screws to fasten the sides together, making sure you pre-drill all holes for their full length to make sure the screws do not penetrate the timber. Counter sink the drill holes to allow the heads of all screws to be flush with the sides. Re-check the timber for rough edges or surfaces and re-sand if necessary.

4. Position the tray so it is squared and lying on a flat, level surface. Carefully lay the ply base over the tray and re-square the tray sides to align with the sides of the ply. Fix the base to the sides using the 50 or 60 mm screws, pre-drilling all holes and counter-sinking the holes. Be careful to make sure the screws will not penetrate the sides of the tray. Once the base is firmly fixed, re-examine the tray for rough surfaces and sand if necessary.

5. While the tray is upside down, lay the three 1” x 2” lengths of timber along the length of the tray. Position one so it runs down the center of the tray, and the others along each edge. Make sure the timber rails are lying on the 1” side so the 2” side will raise the tray well above the ground. Mark the position of each length of timber (including the position along lengths a) with the pencil and drill holes through the tray base using the drill bit used for the wood screws.

6. Set the tray right-side up on the 1 x 2” timber rails and position them to match the holes drilled in the base. Counter sink and then sand smooth the holes, using the dust buster vacuum to remove any debris. Use the 60 mm screws to attach the base to the rails.

7. Using the 6 mm drill bits, drill drainage holes through the base at 300 mm (1’) spacing. Enlarge the holes using the 20 mm drill bit and smooth the edges using the sand paper. Clean the inside of the tray using the dust buster vacuum, being sure to remove all debris.

8. Place the pond liner in the sun for a few hours (if possible) to warm up. Be mindful of cats, dogs and other sharp things that could pierce the liner.

9. Unroll the weed mat over the tray. You are using the weed mat as a kind of blanket to protect it from any unforseen rough edges and surfaces on the tray. You will need enough to cover the length and width of the tray with a double layer, including the side walls. Attach it to the inside of the tray using a staple gun. Hammer the staples so they are flush with the surface of the weed mat. Pull out any staples that deform or otherwise have sharp or uneven surfaces.

10. Position the tray where you are going to use it. Carefully lay the pond liner over the tray, making sure the sheet is squared up relative to the tray’s edges.

9. Add water to the tray using a garden hose, allowing the edges to fill in gradually with the weight of the water. Make sure the edges of the sheet are still square and are positioned so they act as an umbrella to keep the tray as dry as possible. You can add pots when the tray is more than 3/4 filled with water.

10. Once filled, use the staple gun to carefully tack the loose edges of the plastic liner to the side of the plywood base. Do not tack the sheet to the walls unless you are very sure the staple will not go all the way through the wood, as you could puncture the inner liner.

11. Congratulations! Your new Sarracenia tray is now fully set up.

The advantage in using a large tray like these is that they hold a lot more water and are therefore less vulnerable to drying out. It is also easier to set up automatic watering systems using 20 mm irrigation piping. Here is part of my automatic setup – just turn on the tap and everything gets watered. The smaller tubes go off to the trays of Darlingtonia, smaller Sarracenia, Drosera and the self-watering pots for the Cephalotus. The valves control water pressure, making sure the larger outlets are not favoured and prevent the smaller trays filling too quickly. If you make a similar setup, plug in the smaller tubes between the valves, as they will otherwise not have enough pressure to function.



While setting up this type of system can take some time and effort, it is worthwhile because it allows you to enjoy your hobby more. And isn’t that the point of a hobby?

I think so!

A big thank you to John and Sue Creevey for inspiring the tray design shown here! Make sure you visit their website, , if you haven’t already. If you are in Queensland and northern NSW, you can find their plants at most Big W stores with a garden centre. Their Sarracenia are exceptional in being all seed grown. This means every one of their plants are different, which is perfect for collectors seeking something unique. They are my favourite Australian carnivorous plant suppliers and I highly recommend them.