Your rain barrels are full… so now what?
It’s time to start thinking about a simple DIY drip irrigation system. You can use gravity to distribute that precious stored water. Drip irrigation is the most water-efficient way to irrigate, and when you rely on gravity, it is the most energy-efficient as well.
Irrigating with rainwater is wonderful because the plants love the water so much. Fresh from the sky, rain is completely free of the salts, minerals, and chemicals that are found in other water sources. Rainwater also has the perfect pH balance and nitrate delivery to keep plants and soils healthy!
So now that your rain barrels are full, how do you get that super high-quality water over to your thirsty garden?
Rain barrels aren’t pressurized like municipal water (unless you’re using a pump), so getting the water from here to there can take a little thought. This blog post offers a handful of tips and tools on DIY drip irrigation systems and how to irrigate by gravity feed!
HOW TO IRRIGATE BY GRAVITY FEED
The lowest hanging fruit is of course a watering can. Placing your spigot in a convenient location is half the battle – then all you do is fill, water, and repeat!
In this picture, a second spigot on the BlueBarrel Rainwater Catchment System™ faces the back door of the house for easy access from indoors!
But if you’re hoping for some level of automation–and better distribution–there are easy ways to automate a DIY drip irrigation system, too. Our online-store offers a variety of options for drip irrigation kits, soaker hoses, and automated timers–all designed for low-pressure or no-pressure applications like rain barrels.
DIY Drip Irrigation Systems
The great thing about drip irrigation is that it doesn’t actually require any pressure, just water in the line, so as long as your drip line stays below the water level in your tanks, you can irrigate with gravity. There are a couple of important considerations though.
Friction loss caused by water moving along the inside of a narrow drip line does limit the distance that water will travel on a flat site. If your site is completely flat, you can realistically expect about 20 – 25 feet of distribution through your 1/2″ or 5/8″ mainline.
The best way to think about this is to measure a 20-foot radius around your rain water tank. If you have a BlueBarrel system, you can measure 20′ in all directions – for example if you have a drip irrigation connection on Barrel 1, and another on Barrel 10, you can extend each line 20′ in opposite directions. You can also tee-off your main line within that 20′ radius so that you can serve the entire area within the 20′ proximity of your stored water.
If you have any slope at all working in your favor (meaning your rain tanks are installed up-hill from your irrigation area, or the ground slopes down ever so slightly away from your rain barrels), then you’re in really good shape. The water will distribute through your drip line much more freely in this case, and you’ll get much greater distribution by gravity.
Keep in mind that while drip irrigation systems are designed for low pressure, most are specified to operate on 12 – 20 PSI (pounds per square inch) of pressure. A gravity fed system will only offer between 0 and 2 PSI, depending on how full your storage vessels are.
This doesn’t mean the system won’t work, it just means you’ll need to leave the water on for longer in order to get the desired output. For example, your drip line may be rated for 1 GPM (gallon per minute), but a gravity fed line will take longer than one minute to emit one gallon, so observe your system in the beginning to see how much water your plants really need. One benefit to slower water delivery is that it tends to increase the saturation efficiency, so while you may be expecting to double your irrigation time, you may find that an extra 5 – 10 minutes does the trick.
Another consideration is to be sure you are using non-compensating drip line. Water needs to be pressurized to overcome the tight membranes in compensating line, so if you aren’t experiencing success on your first try, that’s one thing to check for. BlueBarrel now stocks two options for drip irrigation kits in our online store – one with inline emitters (for vegetables and row crops), and one with bubblers (for individual control over how much water each plant gets in an ornamental garden). Click on Tools & Accessories to see our full menu of rain barrel and irrigation accessories.
Soaker hoses look like a garden hose, but they have a porous surface that allows controlled amounts of water to seep from the hose walls as water flows through.
If you snake a soaker hose through your garden targeting the root zones of thirsty plants, the water will slowly seep into the soil along the length of the hose.
Soaker hoses work wonderfully for perimeter gardens, or any garden layout where the hose can snake gently to serve all the plants in the row. They can also be wrapped around a tree for the occasional deep watering that those trees so greatly need. (Not tightly around the trunk, but targeting the root-zone out under the tree’s leaf line).
Like drip irrigation lines, most soaker hoses are designed to work optimally with certain amounts of pressure. But as rainwater harvesting grows in popularity, the industry has caught up and now there are special soaker hoses designed to work with no pressure! BlueBarrel is proud to be one of the few vendors that offers no-pressure soaker hoses, specifically for rain barrels and rain tanks!
Rain barrel soaker hoses have a more porous wall, so that non-pressurized water can easily seep into your garden. The rain barrel soaker hose offers much greater distribution than a drip line. Each hose is 50 feet long and according to the manufacturer specs, two hoses can be linked together for up to 100 linear feet of distribution by gravity feed.
Please note that it is recommended to use a 100 micron filter with a soaker hose to keep the pores from clogging. Our drip irrigation connection includes the perfect filter for this purpose!
Drip systems and soaker hoses alike require somebody to turn the water on. But what if you’re not home (or can’t remember!) to turn your water valve on and off?
Automated timers offer major convenience. The only trouble is, most timers that are available in irrigation stores and home improvement centers also require pressure to function properly. We’ve heard many a story of eager rainwater harvesters setting up their automated timers, and walking away proudly only to find that their rain tanks are empty (and their garden over saturated!) by the next morning.
The trouble is, standard irrigation timers require a pressurized water source to close fully, so the risk is draining all of your water unwittingly!
As with soaker hoses, the industry has begun to catch up and there are now a timers on the market that are designed to work without pressure. BlueBarrel offers no-pressure irrigation timers that operate with solar recharge or regular batteries. The timer has two simple dials, allowing the user to set frequency and duration.
With these great new products available to help automate non-pressurized tanks, it’s now much easier to irrigate with collected rainwater in your garden!
Click into our online store above to see the specialty irrigation gear we offer.