How to: Build a Rain Garden

Moisture Control

Rain gardens help reduce stormwater runoff, a growing problem as development increases the amount of ground covered by pavement. They temporarily hold water in a retention area, giving it more time to soak into the ground and return to the aquifer, as well as filtering pollutants before it soaks in. Rain gardens can be beautiful as well as functional.

Step 1:

Assess your yard for the best location for a rain garden. Consider a low place in your yard, at least 10 feet away from the house to keep water away from the foundation and away from large tree roots. Never place a rain garden over a septic tank.

Step 2:

To calculate the size garden you need, decide how much of your home’s roof will contribute to the runoff. The University of Florida’s Extension Service recommends multiplying the square footage of the roof area feeding the runoff by 20 percent for sandy soil and 30 percent for clay or loam.

Step 3:

Once you’ve chosen your garden’s location, make it 6 to 12 inches deep and level, with sloped edges. It will be higher on the bottom edge than the top. The larger the garden, the greater the variety of plants you can use. Select plants that can stand “wet feet” and, ideally, withstand periods of drought, too. Otherwise, you’ll have to water during dry periods.

Step 4: 

Apply several inches of mulch to suppress weeds and keep the soil cool. Keep the plants watered for the first couple of months until they’re established. You’ll need to weed regularly for the first couple of years, until the plants spread sufficiently. After the growing season, allow the dead foliage to remain.

Whitefiles can be nasty suckers

Whiteflies are common on many ornamental plants, as well as citrus. They have needle-like mouths with which they puncture leaves and suck fluids. The top sides of leaves on infested plants become pale or spotted, then turn yellow and drop. The problem often goes unnoticed until an infested plant is disturbed and small clouds of whiteflies emerge from it. 

In addition, whiteflies excrete a sugary substance called honeydew, on which an unsightly black fungus called sooty mold grows. Besides being unattractive, sooty mold may disrupt photosynthesis and cause early leaf drop. Ants feed on the honeydew, often the first sign of a whitefly problem. Insecticidal soap or horticultural oil are the first line of defense against whiteflies. Spray both the tops and the undersides of the leaves. If you choose to use a chemical pesticide, make sure it’s labeled for use on whiteflies and follow the directions. Whichever method you use to get rid of the whiteflies, be sure to follow it with removal of the sooty mold. Spray a mild solution of soapy water on the leaves, then rub them to get the black soot off. Unfortunately, spraying alone won’t get rid of the soot.

Your Monthly Garden Chores


Fertilize citrus for the third and final time this year.

Plant fall-blooming bulbs such as Lycioris (red hurricane lily) for fall blooms. Plant Zephyranthes (zephyr lilies) for flowers next spring.

Divide day lilies, amaryllis and crinum lilies if they need it.

Test the soil in your vegetable garden before planting fall crops.   


Divide clumping perennials such as daylilies, crinum lilies, irises and agapanthus now.

Collect seeds from summer-blooming flowers for next spring. Allow the flowers to form seed-heads, shake the seeds out onto a sheet of newspaper and let them dry. Turn the seeds daily. Store in airtight containers in a cool, dry closet or other dark place.

Buy spring-flowering bulbs as soon as they become available to get the best selection, then store them for planting in November.

Plant your fall vegetable garden: broccoli, cabbage, carrots, collards, arugula, lettuce, leeks, turnips, radishes, mustard, beets, kale, Swiss chard and green onions.

A late crop of summer vegetables such as tomatoes and cucumbers can be planted early in the month.

©2016 PostScript Publishing, all rights reserved. Audrey Post is a certified Advanced Master Gardener volunteer with the University of Florida/IFAS Extension in Leon County. Email her at or visit her website at Ms. Grow-It-All® is a registered trademark of PostScript Publishing.

Categories: Gardening