Potting soil and nematodes in a raised bed, what to do?

8 years ago

last modified: 8 years ago

My fiancee and I discovered her mystery sprouts are tomato plants, and she wants to plant them in a roughly 1x8-foot raised bed beside the porch. We were clearing the weeds and junk (including broken glass and a freaking pipe wrench) from the bed, and discovered two interesting things.

First, the soil is better than the clay elsewhere, but odd. From the vermiculite and peat moss and general light crumbly feel of it, I'm guessing a previous tenant dumped 2-4 inches of potting soil in there, then abandoned it for years, and the weed roots and bugs have been gradually mixing it into the solid clay below. I expect this bed might need some amendment, but without the budget for a soil test, I'm not sure what I might try.

Second, while that bed is teeming with bug life, I've spotted zero earthworms, and several of those hammer-headed nematodes that are said to be earthworm predators. Is there anything I can do besides just picking out those I find, to reduce or eliminate nematode numbers, and bring the earthworm population up?

Comments (4)

kimmq
8 years ago
These simple soil tests may be of some help,'

1) Soil test for organic
material. From that soil sample put enough of the rest to make a 4 inch level in
a clear 1 quart jar, with a tight fitting lid. Fill that jar with water and
replace the lid, tightly. Shake the jar vigorously and then let it stand for 24
hours. Your soil will settle out according to soil particle size and weight.
For example, a good loam will have about 1-3/4 inch (about 45%) of sand on the
bottom. about 1 inch (about 25%) of silt next, about 1 inch (25%) of clay above
that, and about 1/4 inch (about 5%) of organic matter on the top.

2) Drainage. Dig a hole
1 foot square and 1 foot deep and fill that with water. After that water drains
away refill the hole with more water and time how long it takes that to drain
away. Anything less than 2 hours and your soil drains’ too quickly and needs
more organic matter to slow that drainage down. Anything over 6 hours and the
soil drains too slowly and needs lots of organic matter to speed it up.

3) Tilth. Take a handful
of your slightly damp soil and squeeze it tightly. When the pressure is
released the soil should hold together in that clump, but when poked with a
finger that clump should fall apart.

4) Smell. What does your
soil smell like? A pleasant, rich earthy odor? Putrid, offensive, repugnant
odor? The more organic matter in your soil the more active the soil bacteria
will be and the nicer your soil will smell, to a point. Too much organic matter
can be bad as well.

5) Life. How many
earthworms per shovel full were there? 5 or more indicates a pretty healthy soil. Fewer than 5,
according to the Natural Resources Conservation Service, indicates a soil that
is not healthy.

A lack of earthworms may simply mean they do not have the food they like to eat. While organic matter is needed things such as Peat Moss do little to encourage earthworms to hand around.

Your University of Georgia charges $15.00 per sample for a good soil test.

http://aesl.ces.uga.edu/soiltest123/Georgia.htm

kimmq is kimmsr
toxcrusadr
8 years ago
Earthworms are not essential for healthy soil but I can see how you'd want to get rid of the nematodes. I don't have any advice as I've never dealt with them.

As far as amending, it sounds like there is organic matter there but it may not be too rich after years of neglect. I would dig in an inch (at least) of compost. If it needs quite a bit of volume to fill up the bed, you could add some soil, which won't decompose and shrink away. But only if you need to. Add the compost and plant away and see what happens.

How big is this bed? It may or may not be worth the investment in a soil test. Compost can do a lot to bring almost any soil into balance, and it's not likely to go wrong either.
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rhizo_1 (North AL) zone 7
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Jon, the flat worms are Planarians, not nematodes. Those two are entirely different things. You would need a microscope to see nematodes.

The planarian is creepy enough, and can be an aggressive predator of earthworms, as you say. If it's any comfort, they are also little cannibals!

Tox is correct about earthworms, by the way....they aren't necessary. But once you get rid of the planarians, the worms will show up. They just can't help themselves. ;-) I've got earthworms in my yard and gardens, and my soil is hard red clay!
drmbear
8 years ago
If you really have a nematode problem, plant lots of marigolds, and at the end of the year(in late fall) chop them up and stir the remains into the soil. Will do the trick.

Potting soil and nematodes in a raised bed, what to do?

Comments (4)

kimmq

toxcrusadr

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