9 Tips For Watering the Fall Garden
Fall is almost here, and with it, the reduced pressure of watering to beat the summer heat. But autumn is also prime time for adding new plantings, and some climates don't get enough rainfall to ensure proper root development. Gardening expert Katherine Rowe explores what to consider in fall watering sessions to establish thriving plants this season and beyond.
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Fall is a gorgeous time in the garden with overflowing blooms, fresh harvests, and colorful transitions. It breezes in with a relaxed and casual reprieve from summer’s heat. There’s less pressure to water, weed, defend against pests and diseases, and maintain.
Of course, those tasks remain, just to a lesser extent. Soil moisture continues to be essential for trees, shrubs, perennials, and seasonal annuals, so they continue nutrient uptake and photosynthesis before winter. Conditions are ideal for new additions, from trees and shrubs to perennials and spring-flowering bulbs.
Fall is prime for root growth, but it requires sufficient water via rainfall or garden irrigation. Just as cooler temperatures give gardeners a little breathing room, they allow plants to direct energy to root development rather than fully supporting leafy growth.
Autumn brings weather fluctuations, and providing adequate moisture through the swings becomes vital to promoting robust root systems and overall health. But dry spells inhibit microbial activity, and we want those microbes active for all their decomposing goodness.
Proper irrigation depends on your climate, growing area, and plant requirements. Here, we’ll explore guidelines to make fall watering streamlined and enjoyable. It sets the stage for healthy plants to overwinter successfully.
Rely on Seasonal Conditions
Instead of having a set routine, it helps to be mindful of weather conditions and to have those determine moisture needs in the fall. Pay attention to rainfall and dry spells, scaling irrigation accordingly. Keep an eye out for drying autumnal winds, too.
Reduce irrigation timers from their summer run times to account for seasonal variations. Cooling temperatures mean plants lose less water to evaporation. Good, soaking seasonal rains deliver supportive moisture. We want to avoid overwatering and waterlogged situations, which create stress and promote fungal diseases.
Fall is a great time to rethink garden needs and plan improvements, including irrigation supplies to make watering easier. Consider drip systems for pots and vegetable gardens.
For an innovative improvement on the everyday hose, add ease of motion with a self-contained reel. Hoselink’s Retractable Hose Reel takes the frustration out of battling uncooperative ropes. Effortlessly and without bending, the self-winding reel retracts the hose and stores it neatly after use. Don’t let a bad hose wreck the therapeutic benefits of a peaceful watering session.
Check Soil Moisture
Checking the soil with a simple touch test is the best way to measure moisture levels. If you were away from the garden or not sure if rainfall was heavy, it never hurts to check.
Use a trowel or finger to poke beneath the surface. If it’s dry three to four inches deep, it’s time to water. Many species rely on about one inch of water per week for healthy growth. In hot, dry spells, they may need more.
Aim For the Roots
Since autumn is for fostering root growth, watering at the base of the plant delivers moisture where plants absorb it. When hand watering, aim your hose at the plant’s base or around the trunk. Soaker hoses allow concentrated delivery at low volumes and reduce runoff. Sprinklers cover a broad range.
A good rule of thumb is to water early in the day. In warm conditions, this helps with water retention and absorption before evaporation as the day warms. Watering in the morning gives leaves and stems time to dry in overhead situations. It prevents damp conditions that promote fungal diseases. Soaker hoses or trickling hose water are more amenable in evening sessions.
Water Deeply
Let moisture penetrate the soils with a thorough session. Frequent, shallow water doesn’t support strong root development. Irrigating deeply to penetrate surface soil helps roots grow long and stable. Roses and hydrangeas, for example, benefit from sixteen to eighteen inches of deep moisture. This means two to three gallons a week during the hot summer and less in mild conditions.
Water deeply and then hold off for a few days to encourage roots to dig deep into the soil. Deep roots hold water longer, boosting drought resistance, withstanding cold and hot temperature extremes, and physical stability.
Understanding your soil type helps manage irrigation. Whether soil is primarily clay, silt, sand, or organic loams impacts how water infiltrates a site. Sandy soils drain quickly and may need more frequent sessions, while clay compositions drain and absorb slowly. Autumn is ideal for amending your soil to improve structure, boost microorganisms, regulate pH, and add nutrition.
Irrigate Until Frost
Plants absorb water as they continue to grow in moderate conditions until the ground freezes. Once heavy frosts set in and the soil freezes, the plants stop actively growing as roots are unable to uptake water. They depend on insulating snowpack and freeze-and-thaw cycles for moisture in cold climates. In warmer climates, regular rainfall is usually sufficient to keep soils from drying out completely.
Plants that enter winter dormancy (deciduous shrubs like hydrangeas and herbaceous perennials) rely on moisture leading into winter. Evergreens like boxwoods, hollies, and conifers need it to support foliage and roots and prevent winter browning. Hearty roots and less stress entering the cool season are the foundation for successful overwintering.
Foster New Plantings
Young and new transplants or divisions need more than mature specimens to support less extensive root systems. They’re getting their literal footing by developing roots in fall’s prime conditions. Regular moisture, depending on the variety’s cultural requirements, helps them grow and settle in before cold weather.
In the autumnal vegetable bed, most selections require about an inch of water per week. Direct-sown seeds need more frequent attention since their initial roots lie close to the soil surface, which dries faster.
Support Trees
Have you taken advantage of fall’s prime tree-planting conditions? If so, water regularly before winter. About 10 gallons is sufficient for young trees (equal to running a hose for five minutes).
Pour several buckets around the base if a hose won’t reach. Depending on your climate, once or twice a week is enough if there aren’t soaking rains and temperatures are above 40°F (4°C).
Mature trees withstand average seasonal conditions. They benefit from supplemental irrigation during hot and dry spells, but with summer behind us, hopefully, those aren’t stressors. Water around a tree’s dripline, rather than right at the trunk, to reach more roots.
Refresh Mulch
Adding mulch is key to insulating roots and retaining moisture across conditions. In the summer, it helps keep roots cool. In the winter, it protects against fluctuating extremes and icy situations.
Build a two-to three-inch layer or add to existing coverage. Borderline specimens may benefit from extra mulch around their crowns. Keep it away from stems of leafy or actively growing varieties. Leaf mulch, leaf mold, clean straw, compost, bark, and aged wood chips are good options.
Tend to Containers
Those seasonal displays in pots dry out more quickly than in-ground plantings. Check the potting mix regularly and water when it’s dry an inch or two below the surface (a knuckle or two deep).
Plants may be large if they’ve been growing in pots during the warm season. They may need more regular moisture. Or, they may be new displays of blooms, herbs, or veggies showing off the season with tender roots.
Preparing potted specimens for overwintering is helpful in cold climates. Preserve tender specimens by growing them indoors or overwintering in a cool, sheltered space like a garage or basement. To overwinter, water the containers thoroughly before moving them to their protected area. Then, check every two to three weeks for water needs so roots don’t dry out completely. When temperatures warm in the spring, bring the pots back outside and give them a good soak.
Don’t Forget the Lawn
Like other plants, grass keeps growing in early fall while temperatures are mild. Irrigate until turf enters dormancy. Growth stops when temperatures drop, and the ground freezes, usually late fall or early winter and earlier in cold climates.
If you have a cool season grass, the developing roots rely on moisture. Once temperatures lower, reduce the frequency of irrigation by increasing the length of time between sessions. When frost sets in, stop watering, as plants won’t absorb in frozen soils. If in a wet period, hold off on watering and turn off automated systems. Waterlogged situations present fungal issues.
In early fall, continue to mow turf to two to three inches tall. Continue to mow cool season grasses as needed, but not when frosty, which damages the blades.
