When plants are small, aim for the lower end and when they are large, the upper end. Additionally, when it is excessively hot and/or windy, plants may need more than 1.5 inches of water in a week. When using a plastic mulch the entire 1 – 1.5 inches will need to be applied weekly regardless of rain events. With bare ground or when using water permeable mulches (for example, straw or paper mulch), the amount of water applied by irrigation should be reduced by the amount of rainfall the field receives. For example, if it rains ¼ inch, reduce the amount of irrigation water applied by ¼ inch for that week.
The time it takes a drip system to apply 1 inch of water to the soil depends on the drip tube flow rate and width the roots extend which is generally the same as the width of most beds: about 30 inches. The table below shows how long, in hours, to run a drip system to apply 1 inch of water to the 30 inch width based on the drip tube flow rate.
Table 1. The time (hours) it takes to run a drip system to apply 1 inch of water based on emitter spacing and flow rate.
If you have a drip tape with a flow rate of 0.45 gpm per 100 ft it would take 5.8 hours to apply 1 inch of water to the 30 inch beds. Typically this is applied through several weekly applications.
Increase During Hot/Dry Weeks
The opposite issue is raised by hot summer days, so you watch out for any overwatering. When it’s hot, flowerpots and other containers dry out considerably more quickly than gardens and ground landscaping. Examine terra cotta pots in particular because they have a tendency to leak oxygen and water. Although this aeration is generally advantageous, it necessitates more frequent watering. When the temperature reaches 85°, adjust your watering schedule to include more days per week, or even every day if needed. Generally speaking, it’s a good idea to increase the watering if the top 1 to 2 inches of soil are dry. As the season goes on, a soil moisture gauge might be useful for you to keep an eye on
In arid regions like certain parts of Arizona and New Mexico, you might also need to water two or three times a day. Use your judgement and, again, your observation of plant condition. Many plants actually do fairly well in the hottest weather if they are properly watered.
Common Drip Watering Setup
|
Planting |
Recommended Drip Irrigation Device |
|
Large Containers (16+ inches diameter) |
Bubblers w/ adjustable 0-13 Gallons Per Hour (GPH) flow Options Two 1 GPH Drippers One or Two 2 GPH Drippers |
|
Medium Containers (8 to 16 inch diameter) |
Single 1 GPH or or 2 GPH Dripper | |
Small Containers (less than 8 inch diameter) |
Single .5 GPH or 1 GPH Dripper | |
Window Boxes |
1/4 inch Emitter Tubing w/.8 GPH Drippers every 6 inches |
|
Water scheduling isn’t completely hampered if your collection of planters doesn’t have an exact balance of flow rates. Just be aware that you can run everything on a single schedule, watering everything at the same time and frequency, if the moisture plan for each size container is somewhat uniform. If not, you might need to monitor plants that seem dry and manually water them occasionally to give them a little extra moisture. It might be simpler to replace a few of the devices in order to enable a single watering plan in light of that additional work.
The procedure is essentially the same whether you are setting an automatic watering timer or just want to create a routine for manually turning the system on and off.
To find out how your watering devices are penetrating the soil, start with a test run. Turn on the water for 15 minutes. After turning it off, wait 30 minutes and dig below the drippers with a garden spatula or your hands. When many plants are fully established, their roots will reach the bottom of the container, so it’s important to know if the soil is moist enough to reach the depth of your plants’ roots. Try extending the starting plan’s duration by 20 to 30 minutes if the soil isn’t wet. Moving the drippers closer to the plants may also be necessary.
Avoid the most common mistake: overwatering your plants. This is a specific propensity with improperly draining containers. The roots of containers that are submerged in water may rot due to the standing moisture. Recall that the purpose of drip irrigation is not to create puddles in the ground, as you might be used to seeing when using a hose or watering can. The dripping action is very faint and frequently appears as a tiny patch of moist soil. Instead of drowning the plants, you want the water to go through the potting mix and reach the root zone through capillary action.
Plants will require more watering time during the seedling stage, possibly in addition to additional hand watering until they have adapted. However, following that, you can start to strive for a more consistent drip schedule. It is advisable to begin the maintenance schedule with slightly less water than you believe the containers require. Keep an eye on the health of the plants and make adjustments if you notice that they are starting to look wilted and dry. You might be surprised to learn that, once established, annuals can survive with very little water thanks to a drip system that targets their roots for irrigation.
Experts in gardening also advise getting rid of saucers that rest beneath pots. Even though they might aid in keeping the deck clean, their standing water can re-enter the container and exacerbate the rot.
Decrease In Cool/Wet Weeks
In contrast, when the weather isn’t drying out your plants, cut back on the amount and frequency of watering cycles each week. Keep an eye on your pots to make sure the skies aren’t flooding your plants, especially if they are exposed to the rain. You should reduce the drip schedule if the pots aren’t draining properly.
FAQ
How long should I leave my drip irrigation on?
What is the 30 30 rule for drip irrigation?
What is the 200 200 rule for drip irrigation?
How long should I run my rain bird sprinkler system?