DIY Seedling Cart with Flood Trays [Tutorial]

A few weeks ago we put out a video on our seedling cart. You guys were excited about it, so we figured, Hey, well show them how to make one!

What we did to make this work for people with different sized systems was start with a base kit and have add-on kits.

If you want a collection of parts (rather than searching down each individual parts online then paying separate shipping for each of them ugh) you can buy a kit right here.

Lets get started.

The seedling cart consists of three components: the rack, the lights, and the plumbing.

First, set up the rack following the instructions that come with it. Place the shelves 10 inches apart, and leave 14 inches from the bottom shelf to the floor.

The second thing that were going to do is attach the lights to the rack.

Youll notice that we have a wire rack. This allows us to zip tie stuff (like these T5 lights) to it to easily, as well as thread drainage poly through the rack rather than around it.

Before you attach the lights, remove the reflectors. Gently take hold of the bulb and twist it off. Pinch the reflector shroud and remove it, then twist the bulb back on.

We like T5s for seedling racks because they allows us to connect the lights on each shelf together, use only one outlet strip, and keep all the power cords on one side. (This leaves one whole side for plumbing and one side for electricity.)

Careful! Use a *ground fault interruptor (GFI) or a ground fault interruptor outlet to plug in your lights. This will prevent electrical shock.

*A surge protector will not prevent electrical shock.

To connect them together, make sure that you align them so that one round connection and one square connection are on the same side. (Alternate them.)

Use zipties (not around the bulbs!) to attach the T5s to the wire rack. It’s easiest to do this if you have another person to hold the light while you ziptie.

Prepping the flood table trays

There are two big components to the plumbing: the sump and the flood trays.

To prep your flood trays, first identify the high and the low side of the flood trays. You’ll see that the tray has two extrusions protruding from the bottom of the tray; the larger one is on the high side of the tray.

Use a 1 1/4 inch hole saw to drill two holes on the low side for your drain. The holes should be 1.25 inches down from the bottom of the trays upper lip and 1.25 inches in from the side of the mold.

Only the top tray will have a 1.25 inch hole on the high side of the tray.

Each of the holes will accommodate a 1/2 inch elbow drain fitting with gaskets on each side of the tray.

Now take a 3/4 inch barbed elbow fitting and attach it to two inches of poly tubing. This will fit into the opposite side of the elbow drain fitting already in the tray, with one elbow facing downward and one at a slight angle from the bottom of the tray (this will ensure that if one gets clogged, one will continue to function). This will create a siphon for the trays to drain one to the other.

On the top tray only, attach the same elbow drain fitting into the 1.25 inch hole on the high side of the tray.

Set the top tray on the top tier of your rack. Arrange the rest of your trays below it, alternating the high side and low side.

Each fitting will be connected to a 10.5 inch piece of 1/2 inch black poly tubing. Each piece of poly tubing will have a 3/8 inch barbed elbow on the end. Thread the tubing through the rack to reach the tray below it.

To avoid spills and mishaps, we recommend drilling a small hole near the top of the the flood tray and ziptying the drain poly inside the tray using the holes. The last tray will drain into the sump rather than another flood tray.

Once you have your system up and running, we recommend using a timer to flood the system for 5-10 minutes about 3 times each day.

Now that all the trays are aligned and connected to each other, it’s time to add the sump.

Update!If your trays aren’t flooding,this is probably the problem.

March, 2016: If your flood trays aren’t draining like they should be, this could be the problem.

In order to create a siphon, the tubing connection from tray to tray must have an L-fitting on both ends. Without the L-fitting on the bottom, the draining water will never fill the tubing at any point. This “seal” allows the weight of the draining water to draw water down after it, and this is what creates the siphon. If there is no L-fitting, that water just drips down the side of the tubing, and a siphon never occurs.

Installing the sump

We used our base kit for this tutorial, including a 25 gallon sump tank, the pump, black tubing, a quick connect fitting which allows us to wheel the the rack around without taking the sump with us.

Run the long piece of poly tubing from the pump to the fitting at the high end of the top tray. Connect the other piece of tubing to the top of the tray, and connect the two pieces using the quick connect fitting. (If you’re doing this without the base kit, simply run a piece of poly from the pump to the top tray.)

Fill up your sump with the desired nutrient solution, test the plumbing, and add seedlings! Your mobile indoor seedling rack is ready to go.

Save money and time by buying the kit now:

Shop The Kit

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