Q. It has been hot and dry recently and my plants look a little sickly. Should I be watering?
A. Yes. We are about 3 inches or more behind normal precipitation this year. Last year at this time, we were about 7 inches above normal.
These wide fluctuations in temperature and precipitation are what make gardening in our area so challenging.
Most plants need about an inch of rainfall per week to grow really well. The amount of water needed by plants does vary, however – by soil type, exposure and even the type of plant that is grown.
Watering – or proper watering – remains a mystery to many folks.
Many greenhouse and nursery managers report that teaching proper watering is often one of the most difficult tasks to teach new employees.
Lets review a few essential rules of watering so that everyone waters efficiently and sustainably.
Never water plants in the late afternoon or evening. This practice promotes disease. Watering in early morning is the most efficient way to water plants
Contrary to popular belief, watering when it is hot doesnt burn plants. It is inefficient, and cold water can sometimes stress hot plants.
Most established trees and shrubs really dont need much watering even during drought periods. It is best to water deeply and infrequently – if at all. There are exceptions, of course.
Hydrangeas in particular need more water than most, especially if they are planted where they receive afternoon sun. Placing plants such as hydrangea, rhododendrons, azaleas, dogwood or Japanese maples, on the east side of a home or under other trees and shrubs is more sustainable because the plants simply do better with less water need that if they are planting in exposed areas.
In general, these plants – and recently planted trees and shrubs – need deep watering about every three to five days during hot dry periods.
Annual flowers and vegetables usually need watering about every two to three days during summer drought periods. Use a hand trowel to dig down 6 inches near the plants. Water when the soil at this depth is dry. Water long enough so the soil becomes moist at that depth. This can take a while, because generally an average faucet only produces a gallon of water every 30 seconds. It will take several gallons to water an area properly.
Most established perennials will need deep watering about once a week during hot dry periods. There are exceptions: Astibles and clematis are touchy when it comes to drying out. Other plants, such as sedums, barely need water at all.
Mulching conserves soil moisture. Remember, 3 inches of mulch is all you need to help conserve moisture. Please do not pile mulch around the trunks of trees or the crown area of perennials.
Rainwater is best for plants so do your best to conserve it by using rain barrels if possible.
Final rule: Most plants die from overwatering – not under watering. Keep this in mind as we deal with summer drought periods.