To make a garden successful in Central Florida, few actions make more of an impact than soil testing and irrigation. Irrigation is a necessary part of any successful garden management program. The specifics of irrigation may seem a bit trivial, but there are several important questions we need to ask ourselves related to irrigation and irrigating a garden.
Questions and Answers for Garden Irrigation in Florida
- When are we going to irrigate?
- Where are we going to irrigate?
- How are we going to irrigate?
- And why are we irrigating in the first place?
When to Irrigate
Watering your lawn is different from watering your garden. So, let’s cover the first question: when are we going to irrigate? This has been debated almost as much as the age-old question “What came first, the chicken or the egg ?”While I don’t have an answer for the chicken-and-egg question, I do have some helpful information related to irrigation.
It’s more beneficial to irrigate during early-morning hours, for a couple of reasons. Watering early in the morning allows the plants to take up the water that they need and reduces the amount of water you must provide because there’s less evaporation occurring.
If you choose to water in the afternoon, you must realize that much of the water being used is going to be lost to evaporation. Early-Morning watering also allows plants to take up the water they need, and it provides them the time for the foliage to dry out before the evening and overnight. This will help to reduce disease issues.
Where to Irrigate
Where we irrigate is the next question we need to think about The answer to this question seems painfully simple, but there’s actually a lot of science that helps support the answer.
Many gardeners will irrigate the garden with an in-ground irrigation system or some other overhead sprinkler system. Although this does provide the needed moisture to the garden, it also creates an environment for problems. The reasoning behind when, where how and why we irrigate all relate to our integrated pest management plan for the garden. Remember, when incorporating IPM principles into your garden management plan, there are four main categories for Integrated Pest Management controls:
A successful irrigation plan is part of the cultural control measures of an IPM program. When we irrigate our plants overhead or at the ground level, has a major effect on disease prevention, weed and insect management and the overall health of our plants. The longer plant foliage remains wet, the more likely you are to encounter bacterial and fungal diseases.
Watering overhead will keep the foliage wet, whereas watering at the ground level will hardly get any foliage wet at all. Insects can identify stressed plants, so disease-stricken plants will soon become insect-stricken as well.
When we water at the ground level, very close to where the plants are, it reduces the amount of water we use, which also reduces weed pressure, because we are not watering weeds. Only our plants. Watering at the ground level, where the plants are truly taking up the water, will contribute to a better overall health of the plant, which in turn, makes them more resistant to the other issues that we discussed.
Let’s take two different garden plants: green pepper and basil. Both are suffering from disease. The pepper plant has bacterial spot and the basil is suffering from downy mildew. Both diseases are exacerbated by overhead irrigation and foliage remaining wet for long periods of time.
Alternaria leaf spot is made worse by wet foliage and overhead irrigation. Regardless of whether the disease is a foliar disease or not, it will impact the quality and the quality of your crop.
How to Irrigate
Now, let’s look at how we’re going to water. Are you going to use a soaker hose, micro irrigation or overhead irrigation? We talked about overhead irrigation already, so, let’s talk about soaker hoses.
Soaker hoses have a very difficult time delivering water uniformly to all plants in the garden Many times the plant located close to the watering source receives much more water than the plant at the end of your row.
Soaker hoses are an option, but they’re not the best option. Micro irrigation or drip irrigation is a great option. Its pressure compensated and relatively inexpensive. It waters exactly where the plants need it, and it’s simple to design and build a system.
Florida is considered the American Amazon in part due to its abundant water resources, but also because of the unbelievable diversity of plants and animals in the state. Over 50 inches of annual rainfall is wonderful, but we don’t always receive it when we want it. The garden in the summer months is going to be rained on almost every day, but not year-round. Winter and early Spring are often quite dry with low humidity.
Gardens typically will require an inch of water a week. So how often do we water? The answer to that is as needed. When we water it’s much better for plants to water less often and longer duration.
Water once or twice a week when needed and water for a longer amount of time. Watering every day for just a little bit is not nearly as beneficial to the plants. Light and frequent watering promotes shallower root depth as the plant is not required to work for water. So, water less often for a longer duration. Why do we even water?
Why We Irrigate
We obviously can’t control when it rains. However, we can control when we water Getting on a routine watering schedule, will help in many ways. A routine watering schedule will increase your plants’ overall health, which in turn helps the prevention of insects and disease issues. It also will help with preventing abiotic diseases as well. Remember: an abiotic disease is one that is caused by a non-living factor.
If you decide to use drip irrigation or micro spray irrigation, there are a few things to consider: Drip irrigation operates on very low pressure, often 25 PSI or less. Over pressurizing can burst lines and pop off fittings. Pressure regulators can help reduce pressure to acceptable levels. There are also many different delivery options. Bubblers, micro spray heads, drip tape or Netafim are all options.
Filtration is very important when working with micro irrigation. The emitters are very small and small amounts of debris and sand particles can clog up the emitters. Designing and building an irrigation system for the garden will depend on what you’re trying to grow, where you’re trying to grow it and your water source. Using your homes potable water is fine. If you are using well water, it would be wise to have it tested for chemical concentrations. Please note, never water fruits or vegetables with reclaimed water.
In the below picture, you can see pressure regulators, filtration, different supply lines, controllers and the various fittings that you may use to design your system.
Irrigation is a great option to deliver the water that the plants need where they need it and can be used for many different crops with many different applications.
Depending on the soil type, you will want to select an emitter that matches that texture. Sand is a course texture and on the other side of the spectrum is clay soil which is a fine texture. Different types of emitters will emit different amounts of water over a given amount of time. Most of these range from 1/2 a gallon to 2 gallons in home and garden uses. This is amount of water per emitter per hour.
If you have a clay soil, you will want to select an emitter closer to a 1/2 gallon per hour rate. These soils cannot accept as much water over a given amount of time as compared to a sandy soil which can handle a greater volume over time. So, a 2 gallon per minute emitter would be more appropriate for a sandy soil. The Florida Extension Service can help in determining the type of soil you have in your garden or landscape.
Most landscape environments in Central Florida are a mixture of soils, forming a sandy loam. However, many subdivisions are built on extracted soil from digging the required water retention ponds. Often these soils are more clay than sand.
Once you’ve determined your soil, texture and you’ve set up your irrigation system, you’ll need to run it for an appropriate amount of time to make sure that you do not have any major leaks. Also look for any pooling on top of the soil surface, meaning that you are over-applying water. If you see pooling water you may need to set your system for a “cycle soak” schedule.