Frozen Pro-mix?

[kajlo34]

Long story short, the Rona lady sold me two of the 3.8 cu.ft bags (bales?) of Pro-Mix BX for $10 each :) They're normally $28 each, so I couldn't turn it down. The one downside (and reason for the price drop) is that they were open-bagged (just one side on one bag, and a smallish hole on the other; no missing soil even) and scanned as "discontinued". Because they were stored in the "closed for the season" greenhousy section, they were completely frozen. Some sections of the exposed areas actually had visible ice, and the weight proved this. Getting them into my car by myself was a definite chore...

Anyways, I know that soil in gardens *obviously* freezes naturally every year and is perfectly fine to use in the spring, but I'm more worried about nutrient loss from runoff during the thaw than the actual freezing process (I'm not sure how wet the open bags got before freezing). Therefore, my question is: Could there be any significant nutrient loss within the mix? If I use it for growing seedlings, would they need some extra fertilizer at some point?

If the consensus is that it will be unaffected and pretty much exactly like brand-new unopened/unfrozen Pro-Mix, I may have to go back and convince her to sell me the other two bags for my new raised beds ;)

[akgardengirl]

I use frozen Promix every year. It usually sits outside for the winter and I don't seem to have a problem with it. I would buy the other 2 bags as that is an excellent price. It went for $39 on sale up here last year.
Sue B.

[kurt]

If it stayed frozen too long you might have to introduce some new micronize to the mix.Otherwise the freeze should of killed any fungas it might of got when unopened.

[dice]

It does not have much fertilizer to begin with, does it? I would think
you would mix in some starter fertilizer or earthworm castings when
potting up after the seedlings have true leaves. (I use 1/4 worm castings
or a pinch of slow-release organic fertilizer in 3" pots when potting up
sprouted seedlings.)

It will not be sterile with holes in the bags (if it came that way originally).
You might mix 1 part drugstore hydrogen peroxide (3%) to 10 parts water
and use that to wet it when sprouting seeds in it. That will kill off a lot of
spores that sprout when it is watered (the fungus that causes
damping off is the one of concern). If it has mycorrhizae, or if
you add that when potting up, then you want to skip the
hydrogen peroxide (would kill off the mycorrhizae, too).

Other people have had success watering seedlings with
chamomile tea to prevent damping off and fungus problems
in general with seedlings.

[biscgolf]

i use mixes that have frozen all the time as well. i'd go back and buy all they have at that price. freezing shouldn't do anything to the ferts in it which are basically just starter charges to begin with.

[ddsack]

I agree with biscgolf, I have left over mix from the previous year that freezes since all my storage is outside and most years I try to have an unopened bag in reserve as well. Never had a problem.

I have to lug the bags in the house and put them in the basement bathtub to thaw when I need to use them in March, since they still would be frozen outside.

[dustyrivergarden]

It's fine absolutely fine... If i was you I would go back and buy everyone they have. But thats me.

[Longlake]

FYI - HD stores in this area have last year's ProMix on clearance...last night I paid under $5 for the 1.5 cf compressed bales. Frozen, yes. But the bags are sealed. If anyone in MN/WI is looking to stock up, check your local store(s).

Happy Planting!

[kajlo34]

Thank you for your replies, everyone Hope to get the car with the bigger trunk tomorrow and that it's not too late. They were pretty hidden (in a closed-for-the-season greenhouse section), so I'm optimistic. Would a 50/50 mix of Pro-Mix and compost be a good fill for a raised bed veggie garden?

[dice]

Would a 50/50 mix of Pro-Mix and compost be a good fill for a raised bed veggie garden?

That will probably work. (Some people grow fruit trees in containers
in 50/50 Pro-mix and compost. Others use those proportions to make
soil blocks for seedlings, etc.) Year by year the compost will break down
to silt over the summer, so you will want to mix in something each spring
to restore air space that has been lost to organic decay the year before.
(The peat moss in Pro-mix decays more slowly, over about 5 years, but
you still lose a little of the air space that it had originally each year.)

[janezee]

I'd say yes. It's close to what I have and love. I add more compost every fall and spring. Amazing stuff.
j

[dustyrivergarden]

yep that is just about what is in a lot of my beds. along with rock dust.