URBANA, Ill. –Gardeners facing the aftermath of a hard winter often find themselves staring atproblematicraised bedswith significantly reducedsoil levels.
“I remember building and then growing in my firstraised bed,”saysChris Enroth,University of Illinois Extensionhorticulture educator.“Without a doubt, the plants grew exceptionally well. Root crops were a breezeand the weedsalmost non-existent.”
ButEnroth foundchanges afterasuccessfulgrowing seasonwas followed bya standard Midwest winter, and, like most gardeners, discovered his once pristine growing space needed routine maintenance and care, particularlyregardingsoil.
“It is especially important tocare for the soilin raised beds, and there are manymethods of mixing soil and organic material to createthat perfectraised bed fill,” says Enroth. “But even the best of gardeners will need to refresh the raised bed eventually.Settling soil is simply a fact ofraised bed gardening.”
Annually,topdressing with a few inches of compost or high-quality topsoil into raised beds should be enough to keep up with the settling soil level, Enroth says.Butoccasionally a raised bed demandsmore significant attention toitssoil structure.
Most raised beds are filled with some type of compost and topsoil mixture. For newly-built raised beds, there is little soil structure to this freshly installed fill material. Thispoor structure and frequent disturbance by the gardenercausesraised bed soils to settle.
One way to help build structure is to sow cover crops in the offseason. That way roots consistently inhabit the raised bed soil, which helps to build the soil structure. While cover crops won’t halt raised beds from settling it will slow the process and build a vibrant medium for the garden to grow. Off-season cover crops are covered in depth atgo.illinois.edu/OffSeasonCover.
Tilling has its place in gardening but can be overdone. Typically,Enrothrecommendsgardeners till new raised beds, if necessary, to mix the different fill components. Tilling can also be usefulfor gardeners whoneed to make some significant amendments in the future. However, avoid tillingtheraised bed once it is established becauseitcan destroy the developing soil structure ofaraised bed and speed up the settling process.
While often raised beds start weed-free, over time weed seeds will find their way into the garden. Mulching the raised bed can be combined with topdressing tohelpsuppress germinating weed seeds.
Mulch comes in a variety of forms. Typically, vegetables gardeners use mulch that can decompose, such as straw or arborist wood chips.
“Most gardeners realize that raised beds require maintenance,” says Enroth. “And while it may require getting out the wheelbarrow, the effort can be worth it for improved growing conditions, easier access, and more beautiful results.”
Illinois Extension features information on caring for soil atgo.illinois.edu/GoodGardenSoiland ahow-to on raised bed gardening atgo.illinois.edu/HORTRaisedBeds.
SOURCE:Chris Enroth, Extension Educator, Illinois Extension
ABOUT EXTENSION:Illinois Extension leads public outreach for the University of Illinois by translating research into action plans that allow Illinois families, businesses, and communities to solve problems, make informed decisions, and adapt to changes and opportunities.
