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dottyinduncan

Dry postholes

dottyinduncan
13 years ago

We are replacing a fence on our property and the contractor is digging down 30 inches to place the posts. The soil in the postholes is completely dry, right to the bottom. I know we haven't had any rain (until today) since June and we live in a rainshadow area, but this seems very dry to me. Just an interesting observation.

Comments (9)

  • User
    13 years ago

    Depends on where your shallow water table is.

    2.5 ft is nothing. I was completing infiltration tests on holes to 3 ft in areas where the groundwater table is 5 to 10 ft at this time of year and they were dry. Two months ago, the areas had standing water. In the wetlands nearby, the top 6 inches or so were even dryish.

  • dottyinduncan
    Original Author
    13 years ago

    It certainly makes me understand why it is difficult to maintain my garden in the summertime!

  • ian_wa
    13 years ago

    My soil is the same, and unless you live in a swamp this is pretty much what we can all expect. This happens because we live in a climate with DRY SUMMERS! HELLO! :-)

  • Embothrium
    13 years ago

    No, it rains here all the time. Lots of people will attest to that.

    What actually happens on sites that drain here is that the drying starts in spring, even though more or less regular precipitation (and spring) typically extends into early July. If it is not raining one inch per week, not enough is coming down to keep actively growing wet climate plants fully supplied. As I've posted before the Grants (GARDEN DESIGN ILLUSTRATED, TREES AND SHRUBS FOR PACIFIC NORTHWEST GARDENS (original edition)) wrote that watering of plants commencing new growth early in the year (like rhododendrons) needed to start early in the year in this region.

    INDICATOR PLANTS OF COASTAL BRITISH COLUMBIA splits sites up into water shedding, water receiving and water collecting. As mentioned, what your moisture situation will be at a particular time depends on which type of water movement pattern your planting location has. Alan Bloom grew bog and damp ground plants on his place in England by merely burying plastic a ways below the surface, creating artificially impeded drainage (but not puddles), in the same way that a layer of blue clay does.

  • dottyinduncan
    Original Author
    13 years ago

    We haven't had an inch of rain in total since early spring. When Washington was getting mega-rain, we just got grey, cloudy and windy cold weather. This past weekend we got 3/4 inch of rain but since it came down over such a long length of time, it penetrated the soil very well. We live in a rain forest in the wintertime and a desert in the summer. I know the experts recommend watering 1X a week, inch in total. I tried this and found that in between waterings, the soil became so dry that it repelled water and just ran off. I'm interested in knowing how others in this area are watering, whether it is grass, flowerbeds or veggies. And, who is getting the best results.

  • Embothrium
    13 years ago

    Mulch helps a lot, by shading the soil. Water bare soil during a sunny period and watch how the surface of it appears to steam. Plants such as clematis and heaths (rhododendrons, heather, blueberries...) with roots needing coolness may falter or fail in hot soil even if it is kept moist at all times.

  • madrone
    13 years ago

    Like you Dotty, on the Saanich Peninsula we miss a lot of the moisture that Vancouver and Seattle get. We only got rain last Saturday and a light shower on Monday after 6 weeks of no rain at all. I've found the best way to get the water to penetrate is to incorporate as much humus into the soil (horse manure for me, since there are horses next door)and then to cover the whole lot with wood mulch, brought to us from an arborist. Then when you water, it at least doesn't run off but is wicked into the mulch and some even gets to the plants. Whahoo!

  • Embothrium
    13 years ago

    Leave out the amending, just do the mulching instead. You can even get hard ground to soften by putting wood chips on it without breaking the ground up beforehand. Of course, if you are planting at the time or soon after you need to break the ground up - it takes some time for mulching to cause soil underneath to soften.

  • reg_pnw7
    13 years ago

    Here's how I water in my dry gravelly soil garden.

    I don't try to keep the soil moist. I am not willing to use that much water, I think that's socially and environmentally irresponsible. My soil is extremely well drained and gravelly and just simply will not hold water. I water things that need it about once a week. The soil does not get moist, let alone stay moist, that way, but it's enough to keep the grass greenish and the perennials from wilting and the roses from completely shutting down. I've found that after 5 years in the ground, most of my plants don't need nearly as much water as they did even last year. Shrubs that needed weekly water last summer don't need it so often this summer - although it helps that it's been cooler this summer! I use slow application methods - soaker hoses on the roses, an impact (rainbird) sprinkler on the grass, misters or leaky bottles on the shrubs. Otherwise, as you've seen Dotty, the soil is so dry it's hydrophobic. Amending with peat will do that too - dry peat is very hydrophobic, which is why I don't recommend amending soil with peat around here.

    Dry mulch can be hydrophobic too. If you use mulch, you need to apply irrigation BELOW the mulch - install soaker hoses first then mulch, or push the mulch aside when setting out your leaky bottle so the water contacts the soil not the mulch.

    My soil is still always dry to the touch, but the plants are kept from going totally dormant this way, although they're hardly lush. The native plants I don't water at all, they're all well established and are adapted to dry gravelly soil in summer.