GUIDE: Self-Watering Outdoor Container Garden

Open ended 1/4 tubing provides the fastest rate of watering.

Automated gardens are the most efficient way to grow fruit and vegetables.  An outdoor garden can still be automated because the sun is the light and you have no control over that.  Watering and feeding can also be automated to ensure your plants are getting everything they need.  Self-watering containers may be the only way to keep plants from drying up in the middle of a hot summer day.  If temperatures are getting above 85F your plants are probably thirsty!  It is too big of a hassle to hand water your plants all day to ensure they get what they need.  You may not be there when they need the water and your plants should not rule your life.  You may be making a homemade irrigation system to water your plants while you are on vacation, but when you return you will ask yourself, “Why don’t I always use an automated system?”

If you are new to drip systems you will want to read the Introduction to Drip Systems to get acquainted with the parts I’ll be discussing.  For this project you’ll need:

As always, your first step is to plan out your container garden.  Find the arrangement you want to use to maximize sunlight.  Keep in mind that your tubing will have to reach from your reservoir to your container garden.  The size of your water pump will

half inch black vinyl tubing
Look at the arrows - The half inch tube is spraying with plenty of force through two holes.

determine how much reach you have to play with.  Don’t forget your water pump also has to power through your connections and drip emitters.  Water pumps are one of the most expensive parts of the home made drip system, but they usually come with at least a one year warranty.  Once you realize the productivity ratio of self-watering containers you will not want to go back to daily hand watering.

End clamps are an easy way to ensure your half inch tube is closed
End clamps are an easy way to ensure your half inch tube is closed
Kink the tube at the end.

Put the end of the half inch tubing through one end of an end clamp and create a kink.  Wrap the tube around the kink 2-3 times and thread the end through the other side of the end clamp. The result should be a closed off water proof end to create pressure throughout the drip system tubing.

half inch black vinyl tubing clamped at the end.

Put the other end of the 1/2 inch tubing on the end of the water pump.

Make sure the half inch tubing is on tight to prevent leaking and loss of pump power.

Once your pump is assembled you are ready to make your drip lines.  Punch holes in the half inch tubing where you want your 1/4 inch drip lines to start.  Don’t push through the vinyl or whatever material tubing you are using too hard or you will go through both ends and create a leak.

1/4 inch Drip Lines

There is a wide array of drip emitters you can choose from at your hydroponics shop.  You can get inline or compensating drippers which are explained in more detail in the Introduction to Drip Systems guide I mentioned earlier.  You can also get mini sprinklers and other types of emitters for different purposes.  This system is built with compensating drip emitters because the half inch tube sits on the ground and the 1/4 inch tubes climb the length of the container.

T Connection bridging the main drip line to 2 drip emitters.
Straight Connectors are used to connect the 1/4 inch tube to 1/2 inch tube
Connect your 1/4 inch drip lines to your 1/2 inch main line.

Put 1/4 inch straight connections on the end of the drip line with no drip emitter.  The straight connector goes into the hole you made earlier in the half inch tubing.  The connection is how water gets from your 1/2 inch main tube to your individual drip lines.  Fewer connection bridges and fewer drip emitters means more power and further reach.

These drip lines are ready to be staked into their containers.

This is a lengthy guide for a homemade drip system, but bare with me and you’ll be on your way to irrigation freedom!  Next step is to prepare your water reservoir.  You’ll want to drill or burn a hole through the side of your reservoir to put the half inch tube through.  If you just want your lid to sit on top of your reservoir that is fine, you can tape it down.  Expect greater evaporation rates and contamination if you don’t use a sealed lid.  Keep in mind a cleaner grow space is better grow space.

You will have to put the end of the half inch tube that is connected to your water pump through the hole before connecting the pump.  The water pump will not fit through your 1/2 inch hole!  This step is really easy using a drill with a 1/2 inch circle drill bit.  If you are using plastic make sure you don’t crack the side of the reservoir.  If it does crack easily you are probably using a material that is too weak to hold water for long periods of time.

I used a hose to fill the 14 gallons of this reservoir.

For this outdoor reservoir I bought a container that already had holes in the handle.  Since it could rain in the area where the reservoir is it could fill with rain water and knock the lid off the top.  You can drill your own drain holes with a simple drill bit if you are planning to use a container without them.

Once your water pump is in place and suctioned down to the bottom of your reservoir you are ready to add the aeration device.  The air pump will oxygenate the reservoir and ensure the water keeps moving.  Stagnant water can get pretty nasty and your plants love oxygen in the root zone.  If you are unsure on how to set up an air pump check out my guide on installing air pumps in hydroponic systems.

I like to make sure my reservoirs have over flow holes so they cannot flood.

One thing you will probably not find at your local hydroponics shop is a cheap water proofed air pump.  The lack of water proof air pumps seem to

A standard aquarium air pump will work fine. Different air stones will create different aeration patterns. Test different air stones to see what creates the best results.

discourage most hydroponics gardeners from using the natural sun.  A smart do it yourself gardener can find a solution.  You will need to get a plastic container of some sort that comes with a lid that seals tight.  Poke a hole in that container near the top.  Make sure the hole is just big enough for your electric plug and air tube to come through.  I used a screwdriver to create a small crack for both things to go through.

The water proof housing of your air pump.
A small crack in a food storage container.

Put the air tubing through the hole before you connect it to the air pump.  You do not want the hole to be bigger than it has to be.  A large container is safer because the hole can be higher off the ground and away from potential flooding.  Do not put the hole through the lid of the container because rain will get into your electronics!

The electronic air pump is sealed in the container the cord and air stone are on the outside.

I placed the reservoir and water proofed air pump in a covered area with electrical outlets.  I had to use extension cords to get the air pump to reach the outlet.  I also needed a 3-prong extension cord for the water pump.  The digital timer you use to automatically turn your water pump on and off also needs to be in a covered area where rain can’t get into the parts.

Novice gardeners – don’t get the idea air pumps are too complex or unnecessary for you.  That’s your first mistake as a novice gardener!  Automate your irrigation and add oxygen and whatever else the plants need.  Reaching for 100% is how you get perfect plants!  Click on the picture below to see what an air pump does.

Left: Before air pump || Right: After air pump is turned on

Your friends will be jealous when they see how “high tech” your garden is!  Now that your reservoir is up and running you are ready to finish your automated drip system.

Position your containers so that all your drip lines reach your desired target.

Position your containers around the drip line so all the lines can reach their desired area.  I use two drip emitters on most of these containers because they are three gallons and up.  On 1 -2 gallon containers one drip emitter may cover the whole medium over a drip period of a few minutes.  At the very least it will keep your plants alive while you are on vacation.  Having a small drip cycle with outdoor plants will adjust for rain.  Say you are gone for a week and it rains for three of those days.  Those three days it was unnecessary for your drip system to run!  It may have had a detrimental factor because of excessive watering.  Make sure your containers have good drainage and choose your medium carefully.  Well mixed growing mediums are key to ensuring your plan’ts success.  Different plants benefit from different growing environments and growing mediums.

TIP:  People who have been paying attention can skip this tip because they already realized from the article I suggested on Digital Timers, there is a way to automate their watering schedule.  Some digital timers come with a day setting.  The day setting will allow you to run your drip system every other day or in different intervals.  You may want your drip system to run 3 times a day alternating with 1 time a day.  If this tip is confusing you, come back to it later when you have worked with timer settings for your drip system.

DIY Drip System
1/4 inch hose split into two drip emitters for two container plants.

Home Drip System
Compensating drip emitter in outdoor drip system for container gardens.
DIY Drip System Container Garden
Two drip emitters in a homemade container garden irrigation system.
Peppers outside in natural sunlight planted in container with a circle style drip system
Different styles of drip systems and drip emitters can be used to find new ways to efficiently water and feed your container garden.
Inline Drip Emitter Picture
Inline drip emitters can run through 1/4 inch tubing without ending the drip line. They also come in varying drip speeds.

Introduction to Drip Systems

Drip systems are an extremely important component to any top level gardener using soil or top feed systems.    Drip systems can be used outdoors to irrigate small or large gardens and lawns.  They are a great investment for indoor gardeners because it takes the manual labor out of watering and feeding.  It also benefits your plants by ensuring they receive water every day in proper amounts.  The extra time will allow you to create a bigger garden or simply spend less time with your garden for the same benefits.  Indoor gardens must consider the gardener and the plants needs because the relationship is dependent on each other.  If someone feels they are spending too much time in the garden for little reward they may be discouraged and give up the greener lifestyle.

Submersible pumps like this one have rubber suction feet to stick to the bottom of your water or nutrient reservoir

I’ll start by explaining the heart of the drip system.  The most expensive part of your drip system is the water pump.  There are submersible and non-submersible water pumps.  Small gardens and reservoirs will usually use a submersible pump.  If you are setting up your first drip system a small submersible pump should be enough.  Water pumps in the US are rated by Gallons Per Hour(GPH).  The GPH rating of your water pump will come into play when you are deciding what size water pump you will need.  I’ll explain how to calculate the necessary GPH for your drip system in a later article.

The thick blue storage tote is the container or reservoir for the water.

Creativity might be handy when deciding what to use for a water reservoir.  If you are at all concerned about your health, and you most likely are if you have decided to grow your own food, you should try to stick to food grade plastics for all the parts in your garden setup.  You can buy reservoirs at hydroponic shops, but they can have a high ticket.  It is easy to find something around the house or at local department stores to use as a reservoir.  You can also go to US Plastics to order food grade plastic.  A bigger reservoir can mean a longer span in between reservoir changes and topping off with water to compensate for evaporation.  I always get reservoirs with lids or make my own.  Lids will help to prevent algae from growing in your water.  It can also keep pests and other contaminates out of your solution.

The next important piece of the drip system is the air pump.  The air pump brings fresh oxygen from the room through an air tube and out of a submerged air stone.  The air stone will help to keep the reservoir full of oxygen.  The water will bubble and agitate the water so it does not become stagnant.

Drill a hole through the reservoir wall towards the top so you can put tubes and cords through it.

If you are making a home made drip system, you will need 1/2″ tubing for the water to transfer from your submersible pump through the drip lines.  Use a hole puncher made for drip lines to poke perfect holes in the 1/2″ tubing.  The holes are for connectors to be put in to make bridges between 1/2″ tubing and 1/4″ tubing.  Most drippers connect to 1/4″ tubing.  The great thing about homemade drip systems is you can customize them to your hydroponic setup.  No matter what type of garden you have, a drip system should be your next upgrade.  If you already have a drip system than be sure to watch for the upcoming articles about building bigger and more advanced drip and top feed systems.

The air pump delivers fresh oxygen via air tubing to the water or nutrient reservoir

You can get all sorts of connectors to for the tubing so anything is possible.  When the 1/4″ tubing is secured to the connectors attached to your 1/2″ tubing you are ready to add drip emitters, drip lines, or sprayers.  Whatever you choose as your water delivery method, make sure there is somewhere for it to drain off.  In recirculating systems the run off goes back into the water reservoir to be used again.  It’s more economical this way for water and nutrients if you are using them.  The other option is a run to waste option.  I have also put a guide up for building a simple run off table.  Its a very simple design that anyone can build.  Homemade hydroponics can be easy with the right knowledge and the right set of tools.  Refer to the pictures below for more details and if you would like to know more about drip hydroponics check back in the next few weeks to get some in depth knowledge.  Sign up for the RSS to get the articles sent to your favorite feed reader or email address!

Inline drippers have 1/4" tubing on both ends so the drip line can continue running to the final destination. The Red dripper will drop 1/2 gallon of water per hour into the medium while the pump is on.

The open ended 1/4″ tubing will deliver the most water per hour, but small pumps have a hard time holding a steady stream for multiple 1/4″ tubes. Distance also slows down the performance of the pump
Stakes are used to hold the drip lines in place. Make sure the medium is secure around the stakes. Try not to damage roots when placing stakes in growing medium.