How to Water Your Plants (Without Over-watering)
How often should you water your plants? This seems like a simple question, but it’s easy to get wrong. Especially since the most common advice often leads to over watering your plants. So what’s the real answer? Keep reading to find out.
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How often have you read or been given the advice to give your plants the equivalent of 1 inch (2.5 cm) of water each week?
I feel like this is the one-size-fits-all answer to the question of how often you should water your plants.
But this advice is better read as many plants—especially vegetables—need approximately the equivalent of 1 inch (2.5 cm) of rain per week. This is very different than your plants needing to be watered every week.
What tends to be forgotten is that your soil already has moisture in it that your plant roots can reach.
Based on this, let’s answer the question: How often should you water your plants?
But before we do, what if you could transform your garden into a low water garden? Imagine making simple changes to your garden so you could reduce how much watering you have to do. So make sure to grab your free and easy-to-print cheat-sheet all about how to transform your garden into a low water garden.
Water Your Plants – Perennial Plants
The amount of watering a plant needs depends a great deal on the length of its root systems. Plants with larger root systems are better able to absorb moisture from the soil than those with shallow roots.
This means that your perennial plants, (the plants that grow and produce year after year), such as trees, shrubs and even some vegetables generally need a lot less water than your annual plants, which probably make up most of your vegetables.
The perennial plants have much more established root systems, so they need a lot less help accessing water.
But this only holds true if you pick plants that are appropriate to your climate and your property. Good luck trying to grow wetland plants in a very well-drained berm.
When you first plant perennials, they should be watered in just like you would with any other plant. This helps to remove air pockets around the roots and fill in any gaps.
Plus, transplanting is a bit of a shock for most plants. So a good initial watering can really help them get established.
Depending on what you’re planting and when your planting, you may need to give them additional water once or twice a month for the first year. Make sure to water deeply, for at least several minutes, so the soil is wet well down below the surface.
But if your plants are well-mulched, and especially if the surrounding area is mulched, then you might be able to skip watering after the first couple months.
All of this is assuming you’re planting in the spring.
But my go to planting time for perennials is early fall and even through the winter. Planting perennials during this time lets them get their roots more established.
If you mulch the plants, too, then you might be able to skip watering (other than the initial watering when you transplanted them.)
A simple finger test will help you know if your plants need watering. This test will be referenced throughout the rest of this post.
The Finger Test for Watering
The finger test is how I check to see if my plants need watering. This test works best if you have a good layer of mulch around your plants. Without mulch, you’ll need to stick your finger down a couple inches (~5 cm) into the soil instead of just checking the surface. (Bold text indicates when you should water your plants.)
- Stick your finger down through any mulch until you reach the soil below (or a couple inches [~5 cm] into the soil, if you haven’t mulched your plants).
- Check to see if the soil is damp and cool.
- If the soil isn’t damp and cool, then your plants should be watered deeply.
- If the soil is damp and cool, look for signs of wilting or other stress.
- If you see signs of wilting/stress then you may need to water.
- Wait to see if the plants recover in the evening on their own. If they do, and the soil is damp, they should be good.
- Keep observing your plants. And if they show signs of stress like wilting in the morning, or for a couple days in a row, then make sure to water them.
If you see wilting in plants that were recently planted, then you should give them water. Also, trees and shrubs likely won’t wilt. In these cases, follow the rule of giving them water a couple times a month for the first few months and then follow the finger test to determine if you need to water.
I use this finger test for all my perennial plants. And since I use a lot of mulch, I mostly skip watering—this especially holds true for the perennial plants I plant in the fall and winter.
And after the first year or 2, I stop doing this test all together—I don’t want to plant perennial plants that need regular watering every year.
Watering Your Vegetables and Annual Plants
Often when questions arrive around how to water your plants, people are thinking about their garden. Since vegetables are generally planted each year, they tend to need more care than perennials.
This is a big reason why I prefer perennial vegetables. Once they get established, they need far less water. Depending on your climate, you might be able to skip watering your perennial vegetables altogether! Here are some blog posts to get you started with perennial vegetables:
But many people still water their vegetables far more than needed. Often this is based on that old 1 inch per week rule.
A better approach is to use the same finger test that we talked about earlier.
Just stick your finger down into the ground and check to see if the soil is cool and moist. As long as the soil remains cool and moist, you don’t need to water.
Make sure to follow all the steps outlined above for this test. Don’t forget to check for signs of wilting!
The exceptions are seeds that were just sown and haven’t germinated yet, and newly transplanted plants. In both cases, you may need to water more regularly until the seeds germinate, or until your transplanted plants have a week or 2 to get settled in.
Don’t underestimate how deep the roots of a newly germinated seedling can go. Often a seedling that has just come up above ground will have a root that goes deeper into the soil than the length of a pot vegetable starts come in. A seedling can be more resilient than a plant you just transplanted.
If you do this finger test once a week, or every few days during the hottest time of the year, then you will start to understand how your soil behaves in the heat.
You might notice that, after a deep watering, your garden can go 2-3 weeks before the soil around your finger feels dry. Perhaps you notice this after a week. Or on the other end of the spectrum, perhaps you can go all summer without watering at all!
Understanding your garden and your soil will help you make better decisions and give your plants the water they need without over watering.
This will give you healthier and happier plants, and also save you time and energy.
Tradeoffs to this Approach
You might be asking, why isn’t this approach recommended more often if it works so well? There are a couple reasons for this.
The first is that a lot of people don’t mulch their garden. If you aren’t mulching, then your garden soil is fully exposed to the heat of the sun.
Without mulch, you will need to water weekly unless you plant so densely that no soil was exposed to the sun.
But most of the time, people don’t plant that densely. Plus, it takes time to grow that dense of cover.
And I think that even dense plantings should still have some mulch.
There is also the assumption that gardeners are using chemical fertilizers instead of building rich, healthy soil.
But chemical fertilizers don’t build soil or support soil life.
The result is soil that is low in organic matter and mostly devoid of life. Because of this, the soil loses much of its ability to hold onto water or nutrients, which makes your garden dependent on regular watering and applications of fertilizers.
When you build rich, healthy soil that is full of organic matter—pieces of dead plants and animals (including worms and insects), plus the millions of microbes, fungal networks, and bacteria that thrive in healthy soil—you will increase not just the fertility of the soil but also how much water it can hold.
According to the US Department of Agriculture (USDA), every 1% increase in organic matter results in as much as 25,000 gallons of available water per acre.
You can read more about this in the blog post 5 Ways to Transform Your Garden into a Low Water Garden.
The final assumption that is made is that gardeners want massive vegetables and fruits. But these giant vegetables and fruits tend to be far less nutritious and less flavorful than smaller fruits and vegetables grown with less water.
I remember reading about tomatoes being grown with no irrigation in the central valley of California. The producers talked about how their tomatoes were smaller than the tomatoes grown by their competitors. But that local restaurants loved their tomatoes because of how much better-tasting they were.
The same can be true in your garden.
And if tomatoes can be grown without irrigation in the central valley of California then I think there is a good chance you can do it, too, in your own garden!
But you don’t have to stop watering altogether. If you use the finger test, then you will know when to water your plants. This is a much better approach than the one-size-fits-all recommendation that often leads to wasted water and time.
So now is the time to stop overwatering and instead start to observe your garden, so you only water your plants when they actually need it.
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