How to Build your own PATIO GARDEN

How to Build a Patio Garden

A typical Patio Garden

Anyone can build a small patio garden regardless of whether they only have a small piece of open land on their property at the rear or side their house or even if they only have a patio space attached to their apartment in a city.

There are even a lot of people who do not have an actual yard, but they do have a Patio that could be used for growing at least some of their favorite fresh foods.



A Patio garden is actually relatively simple to build and maintain, but it will take a little planning and perseverance to get one started.

Water Drainage Control

To me, the only real and very important difference when planning a garden in your yard and a small Patio Garden is you need to find a way to manage your water runoff from your garden area.

Most apartments with patios, for example, already have some type of water runoff management that will have been built into the building’s design.
The thing for you to remember is you don’t want to irritate your neighbors living below you with your excess garden water washing dirt and other garden debris down and onto their patio at peak rain periods.

So, in order to “keep the peace” so to speak, some water management must be included into your design work. Your Patio garden can be pretty much any size, but for simplicity’s sake, I will describe the design of an 8-foot by 8-foot garden space for a Patio.

Patio Garden Construction

You should start with the base for the small Patio Garden and use one or more pieces of outdoor plywood placed on top of some cheap cinder bricks that will elevate your garden above the floor of the patio itself.
Both of these can be purchased relatively cheaply at your local home repair and garden center. Most of these stores will also cut your plywood to your desired dimensions for free.
The reason I picked an 8x8-foot square design was that you would typically find that sheets of plywood are sold in 4x8-foot sections in the US and picking these dimensions simplifies your construction and overall costs by using standard sized materials.
Space the Cinder Bricks every two feet and then position your plywood over the bricks. With this spacing you can get away with using a 3/8-inch thick sheet of plywood for your garden base.
Please note that you can get these 4x8 sheets cut in half for easier handling if you are going to transport the plywood to your house yourself.
Transporting such large items can be made easier if you have a friend with a pickup truck or open van who will help you. If nothing else works, Bribe them with promises of fresh vegetables when your first crop comes in.

Retaining Wall

Once your plywood is firmly positioned, build a wall around the edges at least 10-inches high using cheap landscaping blocks that you can again find in the garden section of your local Home Center.
If you think these might be too heavy for your patio, try having some plywood cut in lengths that are only 12-inches wide to be used as side walls.
These blocks come in many specific sizes so if you know the overall size of the desired walls, in this case 8x8, it only takes a few calculations to select the right ones for your dirt retaining wall.

Let’s say they have 6-inch wide by 6-inch high stackable blocks in different lengths. You can get seven 12-inch long blocks and one six-inch long block for each side of your retaining wall and they will go together perfectly. Then you can place another layer on top of the first and you will have a 12-inch high retaining wall built onto your plywood base.

This calculates to a total of 7x4x2 or 56 of the 12-inch landscaping blocks and 4x2 or 8 of the six-inch blocks to finish your basic patio garden structure.
More simply, the 12-inch plywood lengths can be nailed together and to the base plywood for a nice border, if you have basic carpenter skills.

Water Liner

Now, at this point you can just throw dirt into the garden bed but I would suggest that you enhance it with a few features.
First, I would get a sturdy plastic tarp and line the garden bed with it making sure that the tarp is large enough to reach the top inside edges of the landscaping blocks (or plywood).

By using a cheap glue on the plywood and on the inside of the blocks before putting the tarp in place it will be bonded to the garden bottom and walls and this will help keep the tarp in place and even give a little support to the walls.

Drainage Bed

Secondly, if you want a way to keep your soil moist but also avoid having problems with mold and even root-rot, I suggest that you put a cheap drain field on top of the tarp.

The simplest drain field would be one like what describe below.
I suggest that you purchase several pieces of plastic water pipe, at least ½-inch inside diameter. Glue them together using the same type of plastic plumbing elbows giving you good coverage for draining the whole garden area.

Using a small drill bit, around 1/8-inch or so, drill a row of holes into the pipe, spaced about 6-inches apart and on opposite sides of the pipe.

Remove one of the shorter landscape blocks from the lower wall, cut a small hole in the water liner and insert the drain end of the plastic pipe assembly into your garden and to the center of the garden space.

It should be protruding about 4-6-inches from the wall, then seal around the pipe with a silicone sealant. Fill the rest of the opening where the landscaping block was removed with a modified block or a piece of wood or whatever you can find that will support the upper layer and the plastic liner adequately.

Then place a bed of drainage rocks over the pipe. This can be achieved by placing about a two to three inch layer of landscape rock onto the bottom tarp and drainage pipe.

If you are worrying about the weight of the rock on your patio, you can even use Lava Rock that is very lightweight relative to other landscaping rocks.

Drainage Bed Shield

I suggest that you use a drainage shield over the layer of rocks. Again, at your Home and Garden Center, get a large enough piece of what is called landscaping paper and cover all of the rocks.
This material will impede the growth of your gardens plant roots through and into rock and eventually impeding the drainage of excess water from your garden.

Planting Soil

You can now fill your patio garden with about 6-inches of good planting soil or other recommended soil. You can purchase bags of simple topsoil and spread it over the drainage shield or you can pick one of the more expensive but usually very good soil mixtures that already have fertilizers included.

Whatever you pick, you will need to water it down and allow the soil to settle a couple of times before you plant anything. Often, six inches of loose soil can pack down to just 2-3inches of usable soil, so be prepared to add soil after the original layer has packed.

Ready to Use Patio Garden

This patio garden is a simple design that you can build on and improve, as you see fit, over time. But regardless, at this point, you have a great place, on your patio that you can use for planting your favorite fresh vegetables, herbs and other plants.
Additionally, with just a little planning you can get multiple “plantings” over the same year in your patio garden.

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