soil less mix question

I bought soil less mix for my seeds and I filled all of my containers with it. I wet if first cause it is so hard to wet the first time... I did not have time to plant all of my seeds in all of the containers and it has been about 3 weeks now. Some of the containers that did not have plants grew some moss or algae in them They are dried out now but did this ruin my mix? Is it still ok to plant seeds in?

You really want your seed starting mix to be sterile and since it's been sitting around and is growing moss or algae it's definitely not sterile anymore. It's possible it might not cause problems, but it's also possible it might so if you don't want to take any chances I would start with fresh mix.

Sterilizing your seed starting mix in the microwave is easy (and you won't have to buy new mix, which may or may not actually be sterile regardless of what the bag says). Be sure to add at least 1 cup of water per quart of dry mix. Cover your container loosely, microwave on high for 8 to 14 minutes (depending on amount of mix and power of your microwave) until you see water droplets from steam condensing on the underside of the lid. Cover the container tightly and let the steam continue to sterilize the mix for at least another 10 minutes. Cool, and use. Keep unused mix covered so it stays relatively free of contaminants.

In my experience, this does not create an odor the way that sterilizing soil mix in the oven does. I use this method when I'm sowing seeds in trays and when I'm putting down leaf cuttings. A bonus is that the steam does a good job of "opening up" the potting mix and making it easy to moisten.

YQ1948, Critters said it all, it really works well when you sterilize your soilless mix. you'll have a lot less or none at all disease problems. one suggestion for dry died out mix is when you wet it put a drop or two of baby shampoo or dish soap in the water and mix. then add it to the soil, the peat will readily mix with it. Jim

Thank you for the suggestion. I had been putting it in a plastic tub and adding water while mixing it with my hands and then putting it into the pots after it was all good and wet. It was kinda fun! LOL

"good and wet" might be too wet... I think DeBaggio said something like, pick up a handful and squeeze it... it should hold together when you open your hand a little, but when you open your hand all the way, the clump should fall apart readily.

I prepare larger quantities of potting mix in an old washtub (not willing to sterilize all the mix I use for transplants, so generally only seed starting mix gets that treatment)... I start with a compressed bale of Pro Mix, add some moisture crystals and (depending on what I'm potting) some slow-release fertilizer, then mix it all up while wetting it down with a trickle of water (DH set up a little "parasite tap" line right above my potting tub)... yes, it's fun!

If you're new to starting from seed, you might find some other helpful tips in this thread, http://davesgarden.com/forums/t/589725/

Good luck, and keep having fun!