Janeybombaney wrote: My question is about about top soil. I am currently baking it at 180 degrees and wondering how long it should have it in the oven! That said, it is now totally dry so I assume it is ready to go. I will, as per the advice on other threads, be mixing it with some play sand. Any advice would be gratefully received.
Jane
Well, I'll admit it - I bake my topsoil! Two things to disclose: I live in the US, and I have a Western Hermann's. I use a mixture of topsoil, coconut coir, and sand in the ratio of 1:1:1/3 (or 3:3:1), respectively (your mileage may vary). I bought a bag of topsoil but I was concerned about what might be in it (pesticides, fertilizers, etc.) and the garden store said they didn't know either (not a warm, fuzzy feeling). So there's this mound of dirt in my back yard left over from some foundation repairs we had done. I know it doesn't have any chemicals in it, so that's what I use.
Before baking the topsoil, I dried it on a tarp in the sun and then I sifted it a few times to get out tiny pebbles, roots, etc. Didn't want anything in it that Scoot might eat. I dried the play sand in the sun as well (my neighbors avoid me now
!) Then I baked both the topsoil and the sand in my oven.
I mixed enough substrate for the whole enclosure, and have a similar amounts of topsoil and sand ready in separate covered bins outside so that I can mix "just in time" substrate, if needed. I've had occasion to bring in small amounts for emergency repairs; I also use this mix for any plants I put in the enclosure. I bring in what I need from my outdoor storage and let it sit a couple of days to bring it up to room temperature. The coir I buy in bricks and mix it up as needed.
These are the instructions I wrote up for myself. Hope they help. Good luck!
• Prepared a plastic tub to put sterilized soil in
• Turned off AC
• Opened upstairs window and kitchen window
• Set up fan to blow out the kitchen window
• Placed 2 racks in the middle of the oven
• Hung oven thermometer from the bottom of the top rack
• Adjusted temperature as close as possible to 180° (it's an old oven!)
• Used round pizza pan and bottom of my largest broiler pan
• Scooped (with ~5in. terra cotta pot) about 1 inch of soil onto each pan
○ 3 scoops for pizza pan
○ 4 scoops for the broiler pan
• Smoothed out soil evenly with large garden spoon
• Baked soil for 30 minutes
○ one pan on each shelf
○ offset - one pan on right, one on left
• After 30 minutes, removed pans from oven and set on top to cool (only needs a couple of minutes)
○ Stirred up the soil a little with the big spoon
• Carefully (!) dumped soil from each pan into the plastic bin
• Lather. Rinse. Repeat.
I found this article to be helpful: "How to sterilize soil: The ultimate guide for every treatment"
https://herbsathome.co/how-to-sterilize-soil/