Covering Some Irrigation Basics

Linda Carloni    Mini-sprinklers are a great solution for starting seeds, especially when paired with a small soaker hose, both run off a drip line.

Because Alameda has a summer-dry climate, the vast majority of plants grown here need extra water during the non-rainy months in order to survive. Even drought-tolerant plants like succulents likely need irrigation for their first summer or two. But when, how, how much and how often to water? Different plants have different needs, but there are some common rules. 

When
Water early in the morning —from 4 to 6 a.m. This allows the plant to use the water before the hot sun rises. Once the sun is out, the leaves will dry, avoiding some mildew problems. The early morning also tends to be still, so there is less chance of wind carrying water away from the plants that need it. 

How
Water can be applied using a hand-held hose and nozzle, soaker hoses of various types, a drip system and sprinklers. 

The gardener using a hose and nozzle gets lots of time outside with the plants — this is great for observing what’s going on with them and seeing problems early, but it may not work for the forgetful or busy gardener. 

Sprinklers can be useful for covering a whole bed, but can be easily blocked by taller plants and may get too much moisture on leaves. 

Drip and soaker hoses deliver small amounts of water either in a precise emitter location or along a hose with tiny holes. Both are commonly used generally with automatic or manual timers for vegetable beds. When using a drip line, more than one emitter may be needed per plant because most of Alameda has sandy soil that drains rapidly. 

One solution when starting seeds or small seedlings is to use mini-sprinklers and a small soaker hose, both run off a drip line. The mini-sprinklers cover the whole bed thoroughly when the seeds are sprouting or the seedlings are new, and can then be easily turned off to rely just on the soaker lines when the plants are more established. 

How much and how often
It depends — and that’s frustrating to novice gardeners. The type and size of plant, the weather (heat and wind) and the soil type all make a difference. There are lots of online resources to help determine how much water a plant needs and the venerable but oft-updated Sunset Western Garden Book is a reliable resource. 

One way to tell if a plant needs water: Use a finger to dig into the soil about an inch. If the soil is dry an inch down, apply some water. If it’s moist, it’s probably good for a day or two, and if it’s wet, the plant needs to dry out for a while before watering. Also, look for wilted leaves — they frequently signal that water is needed.

This information seems complicated, but most plants are tolerant. Trial and error and paying attention to the plants generally leads to good results.

 

Alameda Backyard Growers (ABG) is a network of gardeners in Alameda interested in growing food and donating fresh produce to neighbors who face food insecurity. Find the schedule for ABG’s monthly education meetings at www.alamedabackyardgrowers.com. 

ABG’s Project Pick is always looking for fruit trees to pick and volunteers to help pick them so more fresh fruit can be delivered to the Alameda Food Bank. To sign up, email info@alamedabackyard 
growers.org or leave a message at 239-PICK (239-7485).