Watering a garden is not as simple as just hosing down your garden every evening. In fact if you are doing that, you are not necessarily helping your plants.
When should I water?
I like to water in the late morning. If you water at night, it tends to exacerbate disease issues, and if you have slugs like most gardens, by watering, you might as well be rolling out the slug red carpet. Watering in the middle of the day is not necessarily bad, but you do lose more water due to evaporation. Also, if you water in the afternoon, make sure the water is cold before watering your plants. A hose can heat up pretty quick, and scalding water is not good for your plants. You can water early in the morning if you need to, but the slugs are still active at this time, and I don’t like to help them one bit, but morning is better than evening by a long shot.
How much water do my plants need?
This is a question that is impossible to answer correctly, as it depends on the type of plant, the soil, the temperature, the humidity, the microclimate of the plant, among other things. Having said that, I good rule of thumb is an inch of water per week is what most plants need. I personally use a moisture meter to keep my plants in the optimal moisture range, not too dry, or not too wet. Don't be afraid to let your plants suffer a little. "Whatever doesn't kill you, makes you stronger," works in the plant world too.
How should I water?
If you can avoid getting the leaves wet while watering, then you are doing a good thing. Wetting the leaves can spread disease, and besides it is the roots you want to water anyway. In my opinion a soaker hose system is the best way to water plants, and the best way to save water.
Drip irrigation setup for keyhole beds
How do I get the most out of my watering?
Low volume, slow watering is the absolute best case scenario for your plants. I can't stress enough how important it is to mulch. It is the best way in my opinion to keep your water from running off and evaporating quickly. You can also collect rainwater from your roof in a cistern if water conservation is a concern of yours. I personally collect water from my roof in a cistern that feeds the low volume soaker hose system to water my plots. A metal roof is ideal for this, as it keeps the water cleaner than an asphalt roof. As an aside, I am not a fan of rain barrels, given their lack of capacity.
My watering philosophy
I am not a big fan of watering any plant without thought. For my annual vegetable garden, I have timers on my irrigation system, but I don’t use them. I water only when my plants desperately need it. Granted I live in an area with plenty of rainfall, but last year, once my plants were established, I did not water at all. If you water too much, it washes valuable minerals out of the soil. For example, blossom end rot on tomatoes is caused by too little calcium, which is typically caused by too much water washing away the calcium. Also, frequent shallow watering leads to shallow weak root systems of plants. I highly recommend a moisture meter to help you to determine when to water. If you go the moisture meter route, it is important to have an idea of how deep the root system is of the plants you are testing, so you know how deep to insert the probe.
The first year I planted my fruit and nut orchard I watered some if we had drought for over a week in the summer, but now that the trees are established, I don’t water at all. For my lawn and pasture area, I certainly don’t waste my time or water. I also make use of swales for growing trees. Swales are great tree growing systems that can rehydrate the land.
There are times when you might be more apt to give plants water, such as when you are establishing a transplant or seedling or towards the end of summer when you are trying to establish your fall garden seeds. The key is to put a little thought into watering before dousing your plants.
~ Phil Williams
Phil Williams is a permaculture consultant and designer and creator of the website foodproduction101.com. His website provides useful, timely information for the experienced or beginning gardener, landscaper, or permaculturalist. Phil's personal goals are to build soil, restore and regenerate degraded landscapes, grow and raise an abundance of healthy food of great variety, design and install resilient permaculture gardens in the most efficient manner possible, and teach others along the way.