Greetings! I have a puzzle here. Over the past few weeks, we have had a tremendous amount of rain. The water level in my 11'x30' cistern has gone up 14" in the past week. A bucket left out for 24 hours had 4 or 5" in it. When I dig into the beds all around my house and in the front generally, the soil is damp (naturally). When I dig in the raised beds at the back, only the top 2-3" is damp. Under that, it is perfectly dry. I have noticed over the past few years that there are very few worms in these beds (perhaps because it is so dry?). I don't think this is a new problem - I guess I have never dug before in these rainy conditions. Summer drought is always an issue here, but I have never been aware of this difference in the beds. Background information: The property was cleared twelve years ago (was mostly fir with masses of salal). The so-called soil is shale but there are loads of worms in it. However, it is pick-axe matter, so I bought topsoil (am halfway through my second big truckload - the size nurseries get). The soil in the beds (which were made 6-10 years ago) is the purchased topsoil, a lot of compost made from manure, grass cuttings, and seaweed, more seaweed, more compost from garden and kitchen cuttings etc and some bags of used coffee grounds. Mulch (the years I get to it) has been mostly fine bark mulch. The other thing of note is that the beds in question are over the septic field. Not ideal, I know, but my options are limited. I'll try attaching some photos of the soil (wet and dry) and the site. Any ideas on why the moisture doesn't go through this friable soil more than two inches would be greatly appreciated! Thank you! April
This is usual here, where summers are dry. I expect I could dig around in my yard and quite soon find similar conditions. Some soils may take all winter to become re-moistened to much depth. Spots under conifers may perhaps remain on the dry side throughout the year. These trees may even emit substances that make the soil water-repellant. It is to their advantage to have a dry area around their root crowns, to inhibit fungi that might otherwise rot them out.
Just a thought but it could be a lack of clay in the soil. You can do a very simple sediment test to determine the precentages of clay,silt and sand in your soil. http://www.mite.com.au/soiltest.html http://www.mite.com.au/soiltest2.html
Thank you for taking the time to respond, Ron. Yes, it surely is dry here in the summer, but this problem seems more than that. Greg, I can't believe I forgot about that simple test I could do myself! Thank you for the reminder and the links! (Couldn't quite figure out the triangle one, but that's okay.) Have been testing various places in the garden, including my stash of purchased topsoil and my finished compost. I knew the soil is very sandy, but this was puzzling. I screened everything with a 1/4 inch sieve and didn't take any soil from the top 1/2 - 1". Here is what I found: Purchased topsoil: sand 49%, silt 39%, clay 12%. This is similar to what I found in some of my beds. However in the four beds that stay so dry, I tested just one of them (will do the others tomorrow), I found: 25% sand, 25% silt, no clay, and 50% of... I don't know what. It floats on top. I will try adding a photo. I dried the stuff on top and it looks and feels just like soil. Same stuff is floating on the compost sample as well. My gardening is fairly haphazard, but I have been going on the principle that organic matter is good and so add what I can get my hands on when I have the time. As far as I can recall, what has gone into those beds over the past ten years has been purchased topsoil, seaweed, compost from garden and kitchen waste, fine bark mulch (as a mulch), might have put coffee grounds on them last year, a bit of horse manure once, maybe some peat moss a long time ago. I dried the stuff that floated and it seems like soil in texture (not like bark mulch). So my questions at this point are: 1. What on earth (so to speak) is that floating layer? 2. What might I do about it, since I assume that is one of my problems? 3. Is there something other than adding organic material an organic gardener with 10% clay soil might do to make the soil more moisture retentive? 4. (If 4 questions aren't too many!) I'd like to get a soil sample done so I can be less haphazard (!). Is there some particular place that does this on Vancouver Island? Many, many thanks for any help in sorting this out. April
Another thought in regards to dry soil... When soil is very peat-moss based it sometimes has difficulty absorbing water, and applying a wetting agent to the soil will help it to take up moisture. Dishsoap is a natural wetting agent, and I use it in pots especially where the water just runs out the bottom but never absorbs into the soil. It works wonders. : )
Dry underneath with a few inches of moist above at this time of the year is due to drying out in summer. The lack of deep penetration is common here.
We also have the penetration problem after the long drought. Even if water cachement areas were getting some good falls earlier in October. the levels did not go up till the second down pour as the soil was not absorbing moisture. Many people use wetting agents or water crystals. I use the crystals for any new material I plant such as the juvenile trees in the paddock as I have to wait till other people can water them for me. They also work in pots. My best solution for water retention is both compost in the soils both green and rotted and using mulches. Straw, woodshavings, Eucalypt chips etc. As soils are worked they get better at holding any moisture they get. I am currently holding some tree ferns and a birds nest in a bed of damp wood shavings till they can be put in. Some one elses rubbish our gain. The birds nest is at least 30 years old if I compare it to the one I have had that long. It's huge. I also keep any unplanted pots in a bed of wet wood shavings and they survive our very limiting water restrictions. The rest of the garden fends on it's own with out water of any quantity for months on end. because I have mulched. Just to add I am on bright red volcanic clay (Basalt) brilliant soil but needs the organic to make it very productive. Liz
Plant debris on top of the ground is the most effective approach. Tall forests are able to grow on soils here with very shallow "topsoil" layers - capped by a spongy, water-retentive duff and moss layer.
Ron, I just realized that those beds went into the fall drier than the other beds. So I think you must be right. Whatever the floating stuff is, I guess I just need to keep adding seaweed, coffee grounds, and compost... and I've just found a source for some alpaca manure. And I'd like to get a soil test done as I never have before. Many thanks, April
Watch the alpaca poo if they are grazed. I found out the hard way when I put my boys out put on the vege patch. It was full of weeds some I had not had before such as red sorrell. Liz
Yes I had 2 for about 10 years. They now live at a bed and breakfast amusing the tourists. Got too much to handle. Just some elderly sheep and 4 goats and an agisted horse who all in their own way control weed and grass growth in the paddocks. The paca are very tidy toilet users. They do it in long rows and it is easy to get. Maybe compost it for a while and see what comes up I do use chook (chicken) and goose manure well composted by using wood shavings for their bedding. Liz
