I've used Pro-Mix, Shultz potting mix, and mostly Miracle-Gro. They all work well. Top soil would, I think, become a bit too heavy and compacted. Cheap potting soil is OK, but be careful - some of them tend to turn to cement when wet. If you use it, you might to mix it with some vermiculite to lighten it up a bit. On the whole though, the (soilless) potting mixes work best for me.
I've reused MIracle-Gro from used pots, but I don't microwave it. I just pour a kettle or two of boiling water on it, let it drain and cool, and use it as if it were new. Have not had any problems.
I use a sterile potting mix from my garden center for all seed starting (outdoors and in my GH.)
I used to use a mix I could pick up at Home Depot, but they stopped carying it in favor of mixes with fertilizer mixed in, which I don't care for when I'm starting seeds - the seeds don't need the fertilizer, and it can create some mold problems, I've found.
I would be cautious about baking soil - from the accounts I've read, the smell can run you out, and may render your oven unsuitable for cooking food in it afterwards.
I'd be doubly-cautious about microwaving soil, especially with fertilizer in it. I'm not a scientist, but my hunch is that might not turn out so great.
I've microwaved soiless seed starting mixes before, and as long as you have enough water mixed with them it's ok. It really does work, and doesn't smell up the whole house or hurt the micro. I have never done this with regular or fertilized soil tho!!
I'm very glad I asked this...I was going to use the cheap stuff but now I think I will reuse the MG like PV said. I'll just be boiling lots and lots of water this weekend.
I use MG all the time. I started using it because that's just what happened to be at the store at that time. Since that first year, I've read several times where folks have had problems with other types, so I've stuck to the MG. Can't speak from experience with other types, but just passing along what I've read.
You should be able to find it in your area. I live in the middle GA area and buy it from a local feed and seed. It used to be readily available but the big stores are only stocking MG, ProMix, Jungle Growth and WalMart brand Expert. All seem to have a lot of peat and I have a problem with damping off and fungus gnats, especially in the JG, when planting seeds. You might have more success in finding it at stores that sell to farmers. I paid $14.99 a bag at last purchase. Hope you can find it. It's good stuff.
Thanks Digs, I just spoke with the regional rep and he gave me two numbers to try... and he didn't guarantee that they had it either- just that they might have some of their other products that might be of interest.
Honestly, does it make a difference in the medium used even when you are winter sowing as opposed to under lights? I guess I'm comparing it to the natural conditions that allow seeds to germinate and they would germinate in a regular soil right? I'm just wondering if it would work. Trudi talks about buying the cheapest bag of soil at wal-mart to do this . ?? I'd really like to hear your thoughts! :)
One of the bonuses of winters sowing is you don't get probems like those Digsgardening mentions. I've yet to see any kind of sprout diseases in any of my containers. I've used MG for the last three years and it's worked great. Stays pretty soft most of the spring. Since I never seem to get my seedlings planted until late, that's a bonus for me. The main thing I've lost seedlings to is overheating (read: frying). ;)
I have to say that it's an odd feeling to be practically the only person in the garden centers this time of year...and I've certainly got some odd looks from people when they see what I've bought. I just smile to myself and think about how many plants I'll have come Spring. Then I can walk through a nursery and say...got it, got it, got too many of it, and omg, where am I going to put what I've got? :)
HA YES!! I've been looking all over valueseeds, and two seed catalogs today and just yesterday I was wondering how in the world I was going to start what i already have... Well, I know now!! :)
I'm so excited about this. it's a grat feeling to know how awesome my garden is going to be. Why isn't this a common garden technique instead of growing under lights? So much time and money!!
This is my first year wsing and I am looking forward to avoiding the problems I mentioned. The more pressing problem that I've had, however, is that it's been so warm that I've had seeds to germinate already and had to transplant. Am growing them in the basement and my hoophouse so I'm still using the MetroMix.
Bet you have some spouting seeds, also. Your weather has been mild, too, for January.
I found a half-empty bag of HortaSorb SM which I originally bought for the purpose of creating a moss garden. I actually ended up using it only for pouring on my cat's hairballs before I scooped them up.
Is this HortaSorb SM the kind of thing I might want to add to potting soil when I wintersow? I will probably use plain potting soil from my local nursery.
Also, is there a problem with using containers with ridges? I have plastic water bottles and gatorade bottles with raised and indented patterns. Will the ridges make the soil plug and plant difficult to remove?
In my experience, the ridges on bottles do make it a little harder to get the seedlings out come Spring. The only way I could do it was to slice the bottle all the way through with a box cutter (any cutting tool works, that's just my weapon of choice). And since most of the bottles with ridges are made with harder plastic, it wasn't easy. I tend to use bottles that are a little softer. Of course, if I find any large container...hard or soft plastic...I can't resist it. The softer plastic is easier to poke holes in, too.