Watering Your Plants

     Have you ever asked “How should I water my plants?” You’re not the only one. Watering is one of the most important things for the health of a plant, and doing it correctly is important. Here is a list of general rules to follow when watering your plants followed by a few frequently asked questions that are answered. 

Observe and react

This is the most obvious thing to do that is least talked about. If you overwater for 2 weeks before looking at your plants, the damage is harder to repair. If you catch it at the first signs of overwatering, your chances to save it are much higher. 

Don’t water on a schedule

Water needs change throughout the year. Summer might require daily watering for some plants that only need weekly watering in the early Spring and Fall. Due to this, you will encounter problems if you leave your drip system on for 30 minutes a every 3 days from early Spring through late Fall. 

Checking the soil moisture before and after you water is a great practice until you get a hang on watering your specific plants and understanding your soil needs. If your soil is still moist for several inches below the surface, you may not need to water that day. After you have watered, ensure that you’ve saturated the soil by checking the soil moisture at varying depths nearby the plant to not disturb the root system. 

All of that said, I get it, you’re going to water on a schedule, so do I. The caveat here is making sure to adjust the schedule and regularly check that it is working properly. As the years go on you’ll need to adjust your watering system for different plants. 2 1 gallon per hour emitters on a tree that runs for 30 minutes a day isn’t going to cut it on a tree planted 3 years ago as its root system is now 15′ wide, it need to be adjusted. So, paying a landscaper $40,000 to do everything so you don’t have to touch it doesn’t mean you won’t have to touch it for 10 years. Can your gardener adjust it? If they are willing and can do it, sure, but your average gardener isn’t going to do it unless prompted.  

A weekly walk around your yard doesn’t seem like too much to ask from the average homeowner. Drip systems clog (or get eaten by the dog), sprinklers can get covered or crack, even soaker hoses can crack and fall apart if left in the sun, so nothing is free from needing to be checked. 

Water early morning or early evening

Watering at these times allows the roots more time to absorb the moisture before it evaporates from the soil, and allows it to “prepare” or “catch up” from the heat of the day. If you live in a humid climate watering during the morning is preferred to avoid diseases that are caused by wet, moist conditions that would occur from evening watering. 

Water less frequently but thoroughly*

Living in the desert, I think this part gets misapplied. They get the water less frequently part really well, but the thoroughly portion rarely happens. Having a dripper drop 1/2 gallon daily is equal to watering once a week with almost 4 gallons (probably way more than the plant needs). The difference is that the dripped never saturates the root zone. This is like eating a granola bar every time you’re hungry and instead of filling up with a meal.  You can end up using more water if you water daily on a drip than if you watered less frequently with more water. Your plants will love it more, your wallet will appreciate it, and you’ll be conserving water. 

I personally water a long bed of shrub roses and lamb’s ear once every week and a half to 2 weeks during our 100°F days in the Summer. They’ve been in the ground for about 1 1/2 years, started out as 1 gallon plants, and are growing like crazy. I water them with sprinklers that I leave on for about an hour and I’m done for at least a week and a half in the Summer, and up to a month or two for the other half of the year. It can be done. 

*This applies mostly to plants that haven’t just been planted. After a year or so you can begin to water less frequently without damaging the plant. 

Water evenly to establish a balanced root system

Often leaving a dripper on only one side of the plant will make roots congregate there and not spread out as well. Ideally you would saturate the area around the plant and let the roots expand and grow evenly. A larger, evenly distributed root system will increase drought tolerance. 

Water slowly to allow the water to penetrate the soil instead of running off and causing soil erosion

If the soil is bare, it is easy to cause the soil to run off by blasting a hose over the area. Mulch helps to regulate this, but a slower water stream also helps.

Ensure that water reaches the roots

This is where watering thoroughly really does its work. Watering less often, but deeper ensures that water reaches the roots and saturates the ground deeply to encourage roots to grow deeper. This increases the drought tolerance of your plants. 

Regularly water newly planted shrubs and trees until they get established

New plants have a limited root system that has not yet extended into the ground. Due to this it cannot survive days without watering. Plants need anywhere from 1-3 years before it is considered established and can receive its normal amount of water going forward. Until a plant becomes established, it will need additional irrigation to varying degrees depending on the plant and climate. Trees also fall under this category, but the way they need to be watered continues to change as they age. 

Water container plants regularly

Container plants have their own specific needs when it comes to watering. They need regular watering and for most species this is daily watering. Other things to note about container plants are: 

  • They need a drainage hole
  • Terra cotta pots dry out more quickly than other containers
  • As a plant becomes root bound it will increase the watering needs

Mulch your plants to help with watering

I feel very passionately about mulch. That said, mulching your plants helps buffer any potential mistakes you might make in watering. If you miss a morning of watering and finally get to watering that evening, mulch helps to lessen the harm that does. Mulch also decreases the frequency of watering. If you water once every 2 or 3 days with no mulch, mulching those plants could move your watering needs to once a week. 

A study done showed that plants without mulch used 25% more water than plants with mulch. 

Know your soil

Your soil type changes the watering needs of your plants. To learn more about this you can click the following link to scroll down to that section. 
How does my soil change my watering needs?

Cacti and Succulents

Cacti and succulents have watering needs that vary from other broadleaf evergreen, deciduous, and conifers. They prefer well drained soil, infrequent but deep watering, and have longer intervals between watering. 

Don't plant during the Summer

This is the last suggestion to avoid watering issues. Watering correctly is much more difficult if you’ve just planted in 100°F, dry weather. Having success with summer planting when you’re unfamiliar with plants is frustrating. Your plants aren’t going to grow much in the Summer anyways, so just wait until, early Fall or late Summer when the temperatures are falling below 95°F daily. 

How do I know if I’m overwatering my plants?

There are several signs that a plant will give if it is being given too much water.

      1. Yellow leaves can be a sign of over-watering. They will also be soft and drooping. If they are crispy then you have been under watering. Yellowing leaves can also represent other problems as well such as over-fertilization, underwatering, or lack of nutrients

      2. Yellow leaves are completely yellow not only yellow on the tips, or near the veins on the leaves.

      3. Leaves (the yellow ones) will typically detach easily when pulled if overwatering is occuring. 

      4. Wilting plants (with green leaves) with wet soil is a common symptom of over-watering.

Root rot is a common problem with plants that are over-watered. This is difficult to see in landscaped plants, but can be seen by pulling a potted plant out of the container and viewing the roots. Brown and soft roots indicate root rot, while white and hard roots are typical of a healthy plant.

How do I know if I’m under watering my plants?

You can identify if your plant is not receiving enough water by noticing:

      1. Crisp, wilting, and brown leaves indicate that your plant is saving water for the stem and the leaves aren’t getting the water they need.

      2. Cracked soil on the surface can indicate that it has not received enough water, but is not always a perfect indicator.

      3. Slowed growth or lack of flowering (or flowering in some succulents) can be another indicator of under-watering

      4. Leaves with burned edges can indicate lack of water on certain species

How does my soil change my watering needs?

Soil is not a simple formula. The soil your plants are planted in can drastically change the plants watering needs. Soil contents have these 4 qualities:

      1. Water Retention

      2. Drainage

      3. Aeration

      4. CEC (Cation Exchange Capacity or ability to hold nutrients)

Here are some examples of soils typically found in the High Desert and how they fair in each category

      • Sand: Poor water retention, Amazing drainage, Great aeration, Poor CEC

      • Clay: Amazing water retention, Poor drainage, Poor aeration, Great CEC

      • Average Dirt: Good water retention, Fair drainage, Fair aeration, Fair CEC

      • Hardpan: Good water retention, Poor drainage, Poor aeration, Fair CEC

      • Caliche: Poor water retention, Poor drainage, Poor aeration, Fair CEC

Depending on what combination of soil you have you can water less frequently, or need to water twice as much. When amending your soil (in the appropriate situations) you can choose an amendment that gives you what you need more of.

However, when planting it is important to NOT amend the soil. Yep, you read that right. If you are going to amend an entire area for planting and rototilling the soil together then it is ok, but amending just the hole the plant is going to grow in is not recommended. This creates a pocket where the roots will stay and circle and eventually lead to a decline in health or other problems. For more information about the suggestion to not amend your soil head to our Research Articles page. Incase you’re planting a garden or raised bed, here is a list of soil amendments widely available that you can use:

      • Peat Moss: Great water retention, Great drainage, Great aeration, Amazing CEC

      • Perlite: Poor water retention, Great drainage, Great aeration, No CEC

      • Vermiculite: Fair water retention, Great drainage, Amazing aeration, Poor CEC

      • Sphagnum Moss: Best water retention, Great drainage, Great aeration, Amazing CEC

      • Compost: Fantastic water retention, Good drainage, Fair aeration, It is a natural fertilizer with Great CEC

What should I add to my soil to retain more water?

Mulching your soil is the single best way to retain moisture in your soil regardless of what kind of soil it is. If you’re gardening or making a raised bed, then peat moss, sphagnum moss, coconut coir, vermiculite, and compost all help soil retain more water. Another option is mulching the plant or tree with woodchips, grass clippings, or weed-free hay. This prevents additional evaporation and helps the soil retain water longer. 

What should I add to my soil to add drainage?

Mulching your soil is what I would recommend in almost all situations as it is a long term fix to the problem of no drainage. It helps build the soil over time into a more favorable place for plant roots. If you’re gardening in a raised bed then adding sphagnum peat moss, vermiculite, compost, perlite, or pumice will aid in drainage. While pumice and lava rock are not typically recommended by most, but they are fantastic at aiding drainage and also have water retention components that help retain water while providing drainage. 

What time of day is best to water?

The best time of the day to water is in the early morning or early afternoon. This allows the water to seep down to the plants roots without the loss of water due to the evaporation of the sun. This also allows plants to have water available to pull from to deal with the heat of the sun. There also tends to be less wind in the mornings and evenings which aids in water being efficiently used by the roots. If you can’t water in the early morning then the late afternoon before the sun sets is best. You want to avoid having the foliage wet when the sun goes down to prevent fungal diseases. 

Should I use drip, sprinklers, or soaker hoses?

If you’re wanting the short answer, I use them all. All have advantages and disadvantages. Soaker hoses and drip both water from the ground which is more efficient. Soaker hoses and sprinklers both waste water by watering areas that will grow weeds. Drip irrigation will water directly at the plants roots and no additional area.  When watering trees, drip irrigation can work for the first year or two, but then you need either soaker hoses or sprinklers to water the root systems as they expand. Drip irrigation works best for shrubs and smaller plants with smaller root systems. 

Should I water less in the Winter?

In the Winter the days are shorter which results in less evaporation from the soil. Root activity ceases below 40° Fahrenheit and the water exchange decreases. These both lead to plants needing less water in the Winter. 

Does wind affect how much I should water?

Wind aids evaporation by drying out the soil surface and leaves of the trees and plants. This means that the more wind a plant experiences, the more water it will need. This does not mean that you should drastically increase the water provided in all circumstances. 

Do I water less if I mulch my plants or trees?

Mulch helps the soil to retain moisture by preventing evaporation. If you mulch your trees then your trees will require less water and provide a better growing area for your plants. This is not a significant enough amount that you can skip a watering day early on, or cut the water given in half. After considering all factors of water retention should you then make changes to the amount of water given. 

I’m not a soil scientist, how can I tell what I need?

If you want a test that you can perform on your soil to tell what it needs you’re in luck! This soil test can be performed at home.

Soil Drainage Test

Dig a hole 12″ wide and deep.
Fill the hole with water and let it completely drain.
Fill the hole with water again and note the starting time.

Track how long it takes the water to drain. Does it take minutes, an hour, hours?

How long did it take for the water to drain?

0 – 4 minutes: Fast-draining soil – This area is fine for trees/plants.
5 – 15 minutes: Good draining soil – This is an ideal area for trees/plants.
6 – 60 minutes: Poor draining soil – If soil is draining 1 inch per hour, is not a good area for trees/plants that need well-drained soil.
6+ hours: This is not a good area for most trees, and some native plants, choose trees and plants that normally grow along streams. 

If your soil is taking longer than 6 hours to drain there are options to amend the soil and provide drainage for your plants or trees.