Yard and Garden: Planting for Late Summer and Early Fall


August 4, 2015, 2:26 pm | Richard Jauron, Kendall Evans

AMES, Iowa – Creating a beautiful, functioning landscape depends on putting the right plant in the right place at the right time. As the seasons begin to change it’s important to think about what plants should be planted when.

Iowa State University Extension and Outreach horticulturists describe the correct plants and care to give for late summer and early fall plantings. To have additional questions answered, contact the ISU Hortline at 515-294-3108 or at hortline@iastate.edu.

Fall TreesWhen is the best time to sow grass seed in Iowa?  

Mid-August to mid-September is the best time to seed new lawns and overseed existing lawns in Iowa. A late summer seeding has several advantages over spring seeding. The seeds of cool-season grasses germinate quickly in the warm soil of late summer. The warm days and cool nights of early fall promote rapid turfgrass growth. The growing grass also has less competition from weeds as few weed seeds germinate in late summer or fall. 

Is late summer/early fall a good time to plant trees?

Mid-August through September is an excellent time to plant pine, spruce and other evergreens. Evergreens planted in late October or November may not have adequate time to become established before the onset of winter and could be subject to desiccation, injury and death. Deciduous trees and shrubs can be planted from August through early November. 

Water newly planted trees every day for three or four days and then gradually reduce the frequency of watering. When watering, slowly apply water to the rootball and the surrounding soil. A thorough watering every seven to ten days, in dry weather, should be sufficient three to four weeks after planting. Continue watering until the ground freezes. 

Which vegetables can be planted in late summer? 

Several vegetables can be planted in late summer for a fall crop. For a fall crop, plant beets, carrots, Swiss chard, kohlrabi and kale in early to mid-August, plant leaf lettuce and spinach in late August to early September and plant radishes from mid- to late September. 

Due to hot, dry soil conditions, seed germination in late summer is often rather poor. To promote seed germination, plant fall vegetables when the soil is moist after a rain, sow the seeds slightly deeper than spring plantings and lightly water the row after the seeds have been sown. 

Lettuce seeds are sensitive to extreme heat. To achieve good lettuce seed germination, check the weather forecast and sow the seeds when a prolonged period of mild weather is predicted.

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