Watering Your Plants

How much should I water my plants?

The amount of water your plant needs depends on several factors including: plant species, soil it is planted in, temperature, wind, humidity, and whether or not it is mulched. Here we will focus on how the plant species determines how much to water the plant, if you’d like to learn more about the other factors click on them. The answer to ‘How often should I water my plants’ is not an easy one, but you can follow the guidelines below to determine ‘How much’ you should water. 

The plant species will have directions on how much water the plant needs. Typical words used are: moist, semi-moist, aired, and low.  When low is given as an amount of water needed it means that once established it can survive dry spells. During the growing season you need to water 2 times a week until the plant is established and then 1 or 2 times every 2 weeks. Aired means that a plant requires deep but infrequent watering. This can be 1 time a week if the plant is in a container, or 1 time every 2 weeks if planted in a landscape. Semi-moist is defined by watering around 2 times a week and letting the soil dry out between watering. This is also assuming the use of well-draining soil which is important when using this as a guide. A moist requirement is a place where the soil never really dries out. This is usually near ponds or water features and requires watering 2 to 3 times a week.



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 are a sign of over-watering. This can also represent other problems as well such as over-fertilization or lack of nutrients

      2. Wilting plants 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 doing the following.

      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 or surface roots show signs of stress from drought.

      3. Slowed growth or lack of flowering is another indication of under-watering

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, Poor CEC

Depending on what combination of soil you have you can water less frequently, or need to water twice as much. When planting it is a good practice to plant with 50% native soil and 50% of a soil amendment. The soil amendment will depend on what type of soil you have. Below is a list of widely available amendments 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?

Peat moss, sphagnum moss, coconut coir, vermiculite, and compost all help soil retain more water. Another option is mulching the plant or tree with bark, 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?

Sphagnum peat moss, vermiculite, compost, composted manure, perlite, pumice, crushed lava rock, and Turface all help to add drainage to your soil. While pumice, lava rock, and Turface are not typically recommended, 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. 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 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 drip irrigation, but there is no best choice here. 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. 

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 a tad bit less water. This is not a significant enough amount that you can skip a watering day, or cut the water given in half. After considering all factors of water retention should you 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.