Garden Soil Amendment

Asked January 29, 2018, 12:19 PM EST

Good Morning! I have recently moved into a new home with a large garden area. I plan to begin planting my own garden soon, and would like to amend the soil so it is ready for successful planting. After rains, there are many standing puddles, and there are several other spots that are very hard packed and difficult to dig. I plan to apply compost, but am wondering what other amendment would be best for this soil. The previous home owner grew a garden in this area every year, but I do not know what has previously been applied to the soil. Any information about what amendments would be best, and in what amounts, would be very much appreciated. Thank you!

Clackamas County Oregon soil amendments soil preparation horticulture raised beds

1 Response

We have a considerable number of publications to help gardeners prepare to plant. When it comes to managing standing water, the preferred remedy is to construct raised beds which ensure that roots are above the mire.

At this time of year, hard-packed soil should not be a problem. Challenges such as that are typical in local clay soils when they are dry. The remedy is to moisten them before you dig.

It’s best to dig (or till) the soil when it is moist, not wet or soggy. The easy “test” of when that’s so is to squeeze a fistful soil: It’s too wet if water runs down your arm; it’s just right if the fistful retains its shape when you release your grip but will crack apart when firmly nudged with a finger. If your soil is clay-based as are most local soils, the appropriate moisture content may not occur until May or June.

“Growing Your Own” is an overview of gardening in the northwest, especially for vegetables. Among the topics are building raised beds (page 2) and adding amendments (page 4). (Amendments amount to adding 2 inches of compost over the bed, then digging it in. If you till, make only one or two passes, just enough to mix the compost into the existing soil.) The planting chart (page 7) lists the best time to plant from seed or transplants. (https://catalog.extension.oregonstate.edu/sites/catalog/files/project/pdf/em9027.pdf)

“How to Build Your Own Raised-Bed Cloche” discusses a raised bed with an optional “cover” to assist with growing veggies through the winter. Consider raising the bed at least 8 to 12 inches above the surrounding soil. (https://catalog.extension.oregonstate.edu/sites/catalog/files/project/pdf/ec1627.pdf)

“An Educator's Guide to Vegetable Gardening” is a primer for growing vegetables in the northwest. (https://catalog.extension.oregonstate.edu/sites/catalog/files/project/pdf/em9032.pdf)

Then, if you’re interested in gardening year-round, “Fall and Winter Vegetable Gardening in the Pacific Northwest” contains the critical information you need. (https://catalog.extension.oregonstate.edu/sites/catalog/files/project/pdf/pnw548.pdf)

Enjoy your new garden!