Saturday, November 28, 2009

Positioning A Grow Bed

So it's time to mount the grow bed. However, there are a couple of things to consider before you do it.

Location - You are going to need sunshine, so pick a spot that will get a good amount. Also, keep it close to the pond and close to the pump. Too far and your pump might not get the flow you expect. You will also have more pipe that you will have to bury, and nobody likes digging except maybe Satan.

Height - The output will be using gravity as the main force to return the water to the pond. The drain will be at the bottom of the grow bed and needs to be well above the water line of your pond. Make it as high as possible, but keep the top of the bed at least a couple feet below the fence-line or your neighbors might complain. And remember that creating too much head from your pump will lessen its output, so don't go too high.

Why the height of your grow bed is important:
It is important to provide good water circulation inside your pond for aeration. Aeration is much more effective with good circulation. In fact, at least one study that I have read says that circulation is the best form of aeration. But at minimum, by moving deep water to the surface continuously, you will increase aeration dramatically. So, in order to create a good flow for circulation inside the pond, get the bed off the ground as high as you can without causing negative effects, such as no access to the plants, or creating too much head for your pump.

Image shows a 4 foot drop in my configuration.
Combined with the first line(which has about a 6 foot drop),
this creates a great circular water current in the smaller pond.

So how high should it be?
There are too many factors to consider for me to give an exact height. Every system will vary. How many beds you have, number of ponds, aeration method, type of drain, and pond size are all things that will determin how high you mount the grow bed. If you just have a single pond, and you have an aeration system that can create good circulation, such as the aeration method I use in my larger pond, you can keep the grow beds fairly low just a foot or two above the water line. But if you are using a bubbler, any other method of aeartion, or you have more than one pond, you will need extra height. The higher, the better. If in doubt, go higher.

Tuesday, November 24, 2009

How To Make a Grow Bed (PART 2 - Mounting Support)

This instruction is for the mounting support that will go underneath the grow bed and is attached to the posts. Once the mounts are in place you just set the grow bed on top of it and secure it.

The above photo was taken when I was designing the mount and is not exactly what the final support looks like, but it does give you a good idea. An additional three posts(one 4x4 and two 2x4 posts) and a 4x4 support beam are added to the final design.


5 - 2" X 4" X 8' Studs
1 - 4" X 4" X 8' Post
10 - 90degree angle brackets(any type, make sure they are strong)
20 - 3" Deck Screws
50 - 1" Wood Screws or Nails

Cut your 2x4's at the following lengths:
2 @ 48"
3 @ 29"
2 @ 77"

Using the 3" screws, screw the boards together as shown in image 1 below. When done with the 2x4's, add the 4x4 beam with the angle brackets and 1" screws. I could try to explain it all, but I think it will be easier just to follow the drawing(image 1). Use the remaining angle brackets for the inside corners where the longer 2x4's are connected.

The green lines show where the posts will be once it is mounted. The grow bed will then set directly on top of the mount. Mounting instructions will be next.

Here is a photo of what it should look like when mounting the grow bed:

Get ready to dig for the next part. Oh what fun.

Friday, November 20, 2009

How To Make a Grow Bed (PART 1 - The Grow Bed)

This will give instructions for making a grow bed box out of wood. This does not include the mounting, underneath support, or the liner and drains. Each of these steps will have there own set of instructions. I feel this is a better way to go. A few small sets of instructions rather than one massive set of instructions is easier to follow IMO.

So here we go, the first of daily(or almost daily) instructions to cover everything this project entailed.


Materials needed:
15 - 2" x 4" x 8' fir or redwood studs
1 - 4' x 8' x 5/8" plywood

9 - 2" x 4" x 8' redwood studs(you can also use 1x4 redwood)
1lb - 1 5/8" wood screws
1lb - 2 1/2" or 3" wood screws
12 - 90degree angle brackets(any type, make sure they are strong)
4 - 24" strap ties(any type and you can get away with using only 2)
1lb - 1" nails or wood screws

Step 1
Take 2 of your studs and lay them on a flat surface. Spread them 4 feet apart and place the plywood on top of them. With the studs smaller sides contacting the floor and the plywood, line up the studs with the edges of the plywood. Secure them by screwing through the plywood into the studs every 6 inches with 1 5/8" screws.

Now measure the distance between the two mounted studs, it should be 45", but always measure for certainty. Cut 2 boards at that length using 1 of the studs. Now place the newly cut boards in between the mounted studs and secure with 1 5/8" screws by screwing through the plywood into the boards. Next, connect the mounted 2x4's at the corners with 3" screws. Image 1 below shows the details.

Now turn the plywood so it is face down with the mounted 2x4's on top. Take 8 of the angle brackets and mount them as shown in image #1 below.

Step 2
Now you are going to build the side walls up using 2x4's. You will want to take the studs and build 4 boxes. You will do as you did when mounting them to the plywood, but this time you will be adding the studs in between to form the box first. Using the exact same measurement(45") cut 8 lengths of board using 4 studs. Line up 2 of the newly cut boards between the ends of two studs and screw them together using 3" screws as in image 2A below. It is important that all these boxes are the exact same size, 4' x 8'. Don't worry if the corner angles are not exactly perfect at this point.

Once the boxes are complete take one and place it on top of the box mounted to the plywood. Take a 3" screw and, going in at an angle, mount it to the box below it. Repeat this with each box until you have an almost complete grow bed. Image 2B below shows the details.

Now take a strap tie and secure each board to the one below it on the inside of each wall using 1" screws or nails. Repeat for each side.

Step 3
Now we will make it look better and at the same time make it stronger. Take 1 of the redwood studs. Find the center of it and draw cut lines at 45 degree angles as shown in figure 3A below.

Now take 2 redwood studs and cut the ends at 45 degree angles to match up with the smaller boards, forming a rectangle. Screw them together with 3" screws as shown in image 3B below. You will first have to drill guide holes to prevent the wood from splitting. A 1/8" or a 5/32" drill bit will work. Once you have it complete, set it on top of the grow bed and secure with 3" screws as shown in image 3B below.

Now using the remainder of the redwood cut and secure trim as shown in image 3c below. You don't have to use the exact patterns I did, but make sure you have at least one center board that connects all of the wall studs. This will prevent the walls from bowing out when filled and only needs to be done on the two long walls.

On second thought, the trim is better put off for now. You can still do it now, but it will make certain things more difficult if it is in place. A better time to add the trim would be after it is fully functioning and as the final detail. So the option is yours, but I recommend waiting until the end.

In the picture above I used a different, and stronger pattern. I was running out of wood and money at this point, so the trim is not all redwood.

That is it. Next I will show you how to make the mounting supports for the bottom of the bed once it is mounted.