sterilizing seed starting mix : LUSENET : Countryside : One Thread

Could someone tell me how to sterilize seed starting mix. I have some mix that has been open for a long time and I'm afraid some nasties might be living there. I can't wait to get some seeds started but I don't want to lose them to damping off. Thanks. Marlene

-- Marlene Leiby (, February 07, 2002


Microwave till hot (never tried it) put in the oven or on top of the wood stove until dry, the re-moisten with sterlized (boiled) water.

-- Kathy (, February 07, 2002.

The oven or woodstove thing really works. BUT.. in the oven it tends to smell a bit... The question is.... is the smell worth not having to buy new.

-- Kristean Thompson (, February 07, 2002.

For small amounts the microwave works, but you should stir it at least once to make sure the center is hot, if it is too hot to touch it's done.

For just a few pots [clean pots] pour boiling water over the soil in the filled pots in a clean dish pan, cover it all with plastic and let cool.

For lots of it, put it in a kiddy pool wet it, cover tightly with clear plastic and let the sun do it, remember to stir it and check the temp. of course this way works best in the summer, and off the top of my head, I think the temp. needed is 180.

-- Thumper/inOKC (, February 08, 2002.

Yeah, the microwave thing works - about 5 min per medium-large clay pot's worth. Makes your house smell VERY earthy, though.

-- Soni (, February 08, 2002.

Damping off is due to overwatering and not enough air circulation. I use 1/2 garden soil and 1/2 compost and don't sterilize it. Have never lost any seedlings. I don't think that sterilizing your potting mix would really hurt it, but I wouldn't do regular soil. The soil is full of microbials that help the seedlings to fight off the fungus's that would kill them.

-- Lynelle SO.westernVA (, February 08, 2002.

Oh Microwave..Schmicrowave....depending on where you live, you can put a black garbage bag on the ground in the sun, spread your mix out on it, cover it with a another black garbage bag, put some stones or bricks or boards on the edges to keep in the heat... Voila'

-- Harmony (, February 08, 2002.

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