Watering Annuals

Annual plants require soil that is both well draining and moisture retentive. This may seem like a contradiction in terms, but the roots of annuals tend to be shallow and will dry out quicker than a deeper-rooted perennial or shrub. Proper watering techniques and timing will ensure that annuals produce flowers or fruits up to the first frost of fall.


How To Tell If Annuals Need to be Watered

Annual plants will show signs of drought stress quickly and can rebound if rescued in time. The leaves will droop and may begin to curl; flowers will drop off while still in bud; and the color of the foliage may fade and become yellow. These are also signs that the plant is being overwatered or needs better drainage. If the annual is in a pot, tip the plant out and look at the rootball. Dry soil indicates stress from lack of watering, while wet saturated soil with darkening roots indicates a need for better drainage. Although annuals will quickly recover with deep watering and a little shade, the plants will lose some vigor every time they have to be revived and may stop growing altogether.


How Often To Water Annuals. 

The watering frequency depends on whether the plants are in the ground or a container and if there is natural rainfall during the growing season. Generally speaking, one inch of water a week is enough to keep most plants healthy and vigorous. Water newly planted annuals when the top 1-2 inches of soil or potting mix are dry. As the season wears on and the summer gets hotter, watering may need to be done daily, especially for containers and hanging baskets.

Overwatering of annals is very common if you use an automated irrigation system on timers and have regular rains in the summer. Either use rain sensors for your drip system or change the settings manually. Overwatered annuals are much more likely to die than annuals that are underwatered routinely.

The size of a container will dictate how often an annual needs to be watered. Larger planters and pots hold moisture longer than small pots. When annuals reach full size, they require more water to keep their large, shallow root systems hydrated. Check for watering daily as plants fill in containers and the weather turns hot.


Best Time To Water Annuals

Time of day matters when it comes to watering annual plants. Most annuals have fleshy leaves and stems that can contain up to 95% water. Plants are most receptive to watering early in the day when the soil may still be damp from heavy dew. It is best to keep water off the foliage as much as possible to reduce the risk of foliar diseases. Although morning is the best time for watering, do not hesitate to water an annual that shows signs of water distress at other times of the day. A good soaking can quickly perk up a dehydrated annual. 

How to Water Annuals

Step 1 - Check for dryness of the ground or container.

Using a finger, feel to see if the top 1-2 inches of soil are dry. If the soil is still wet, do not water it.

Step 2 - Apply water from a watering can or hose.

Saturate the root zone until water pools on the surface of the soil. Wait a few minutes for the water to soak in thoroughly. Apply more water to ensure the whole area is saturated.

Step 3 - Water a container or hanging basket thoroughly.

Water the surface of the soil until there is runoff from the bottom of the container. Wait a few moments for the water to stop dripping, and then water again to ensure all of the soil is saturated.

Annual Watering Tips

  • Overwatering and underwatering symptoms are similar and indicate an immediate need for action.
  • Apply water until it runs from the drainage holes of the container.
  • Use rain sensors on automated watering systems to prevent overwatering of annuals.

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 Author Robbin Small - Published 1-12-2023