Lot's of rotted compost/manure will buffer any ph problems. Rake it into the top couple inces of soil.

Well, they manufactured that soil most likely and didn't scrape it from somewhere fertile like Enumclaw or Skagit or Cowlitz. So of course it is going to be lacking some things. The second thing is the little test kit you bought should be taken with a grain of salt.

Nonetheless. It is likely your purchased soil is missing clay and so the ion exchange is low and slow, so you have to wait until the organic matter in the purchased soil starts coming alive with critters. And it is likely you have sufficient OM - do a jar test and you'll see that you don't need to add manure or compost.

Give it time, the soil critters will start migrating there and things will start working.

Dan

If you did the soil test with a home testing kit, I wouldn't put much stock in it :-) First, I'd be very surprised if your pH tested as alkaline (you did use distilled water when you tested, right?). Virtually all western Washington soils will test out at slightly to moderately acidic. That is just the nature of our underlying soil components and a factor of our location and rainfall levels. From the WSU esxtension office: " Most soils in western Washington are naturally acid, having pH levels reported from 4.0 to 7.0 on soil tests, which is quite a broad range. The most common readings from soil laboratories of soils in western Washington fall between 5.0, 6.0 and 6.5. A soil with a pH of 5.0 is ten times more acid than one with a pH of 6.0, 100 times more acid than a soil with a pH of 7.0 (This pH scale is logarithmic, like the Richter scale for earthquake intensity.)

Soils in western Washington develop acidity in part because wet conditions cause leaching of nutrients from the top layers of soil. Some of the nutrients washed down are the positive ions of calcium, magnesium, and potassium that help to raise the soil pH. As these ions are removed, they are replaced by hydrogen and aluminum which increase soil acidity. Many of you may have lived in arid sections of the American West where the soil is distinctly alkaline. High pH levels also tend to occur where the native rock is calcium-rich limestone (think of the "white cliffs of Dover"). Native rock in western Washington isn't limestone."

And home test kits will never measure any significant levels of nitrogen - it is the most mobile and volatile of the plant nutrients and even professional testing labs have to use special tests to measure this element.

FWIW, most bulk soil providers in our area (you're in Bothell, right?) deliver a decent product - Cedar Grove, Pacific Topsoils, etc., produce perfectly acceptable soil mixes. I've used most of them myself, both in my home garden and as amendments or needed imported soils for clients' gardens and have not found any of the biggies to be problematic or lacking in any significant way. I especially favor Pacific's 3-way mix for a great, all purpose soil. Excellent drainage characteristics and plenty of OM.

I would continue to add compost, your own if sufficient and ready or purchased, if it is not. Apply it as a mulch or topdressing and there is no need to disturb existing plantings. And as Dan says, give it time. Improving soil conditions is not an instant process.

You can also dig some smaller trenches in the new soil and put in native soil to transplant soil microorganisms. Make sure its humusy and none of that glacial till if you have it where you are.

Dan

The only "soil" that I have available to me is the powdery sand that is below the 1/2" of existing bark on the lot. Since my compost is not done, I'll buy several bags and dig it in where I can, and mulch where I can't.

GardenGal - I used a mixture of Pacific Topsoil's pacific garden mulch and screened compost mulch that I mixed with my existing sand. I guess I should have added some peat, but it isn't a heavy mix so I didn't think it was necessary. My concern is that perhaps they skimped on the nitrogen and all of the carbon has sucked it up while decomposing.

I didn't expect exact results from the home soil test, but the evidence that the soil isn't so good is pretty clear to me based on the way plants are responding to this versus a normal potting soil or my existing pure sand. Nothing is dying, it's just not growing.

Is there anything besides adding compost that I can be doing to get this soil in tip-top shape for next year?

I would grow a cover crop. Roots go deep and wide spreading organic matter and opening up soil. Something that will die of in winter (around here I use oats). Use some good organic fertilizer to give it lush growth.

>(I have basil side by side in 2 pots, one with that soil and one with miracle grow, and it's night and day difference).

I think Miracle grow has fertilizer added to their mix don't they? I haven't used it for a few years, but in my past experience Miracle grow works wonders the first year or two and then kinda peters out and works like plain old topsoil. ...just a thought :)

That 'powdery sand' is likely glacial till and may prove to be a drainage issue - you may want to see if there is a perched water table complicating things (altho this year might make it a non-issue, but not next year).

The glacial till will give some minerals and CEC but your young imported soil needs critters to do all the things soil does. The manufactured soil is not real soil - it is likely a sandy loam or a loam, but it was made by grinding up stuff. It needs to have critters to complete the soil for your plants to thrive.

I don't remember the nurseries around Bothell, but surely there is somewhere that has a mix for beneficial bacteria/fungi. And go to a friend's house with an established garden and ask them to fill a 5-gal pail. Or you can make a road trip to Rainier and stop on the Plateau and take some of that soil. My garden exploded out of the ground every May.

Dan

Are you really saying the plants in 'pure sand' are growing better than the ones in the amended soil? Frankly, that's a little difficult to accept ;-)

Without further details, I'm going to assume not enough amending was done of the 'pure sand' to make a difference. Organic matter or compost doesn't go nearly as far in a very sandy soil as it does in a heavier clay soil nor does it last as long. 6cy of compost represents only 2" added over 1000sf....that's not very much and hardly enough to make any impact as far as improving the soil by making it more moisture retentive or increasing fertility. I'd probably triple that rate of application, as well as use additional compost to mulch.

FWIW, both Pacific Topsoil products you used are excellent soil amendments with relatively high fertility and virtually entirely OM. I just don't think you used enough :-) Planting a cover crop on your veggie beds is an excellent idea for the winter months but of course will not work in beds with permanent, ornamental plantings. Just keep adding a good thick layer of compost - your own or purchased - as a mulch wherever you can.

As I stated before, soil improvement is not an instantaneous process. It may take multiple growing seasons before you have incorporated enough OM to maintain adequate levels and desired soil fertility. In the mean time, you might want to consider an all-purpose organic fertilizer (I like Dr. Earth) to fill in the gaps.

Thanks guys, I'll give those things a try and see what comes of it.