Pro-Mix HP Your thoughts?

[Yak54]

Reading the details on the various Pro-Mix types, a compressed 3.8 cu ft bale uncompresses to about 5 cu ft. The HP (high porosity) appears to be well suited for low light (indoor?) starts. I see some online prices at about $39. That's about what I paid, local pick-up, 3 seasons ago. I now need to restock.

Since I will be attempting indoor starts under grow light for the first time in about 20 years, I'll look at both HP and BX. Maybe buy both, and blend the two for some starts? The local gardening center hasn't had their shipment arrive yet.

Hey Tormato... How far away are you from Marlborough MA ??
For starting tomatoes & peppers this stuff is the best I've used in 30 years of seed starting.... Magik-Moss. https://www.google.com/url?sa=t&rct=j&q ... kSoEpcYpkc

Dan

[Seven Bends]

I use UltraSorb Floor Dry from AutoZone and haven't had a problem with particles sticking together.

PRODUCT DESCRIPTION
UltraSorb premium oil absorbent is an all-purpose absorbent designed for the quick clean up of water, oil and grease. Made from diatomic earth, a naturally occurring material with superior absorptive ability, this high quality product delivers 50% more absorbency per pound that clay alternatives. Ultra Sorb premium oil absorbent is available in a leak-resistant and moisture-resistant poly bag.
https://www.autozone.com/shop-and-garag ... /36015_0_0

Just be careful with this stuff. It's a lung irritant which can aggravate asthma and other respiratory diseases. Long-term exposure at significant levels can cause silicosis, and one of the ingredients, crystalline silica (a.k.a. quartz) is considered a Group 1 carcinogen. The MSDS (material safety data sheet) advises wearing an N95 type of respirator when handling it (luckily, many of us have a drawer full of these at this point!).

ultrasorb msds.pdf

[bower]

I was okay with the Promix HP I used last season mixed with compost. But seriously, the stuff is peat. It stank (like peat) when I opened the bag. And I didn't see any special benefit from the myco difference in any Promix I've used. I don't see much special about the product, so if you have to ship it in I think you're better off getting whatever peaty/perlitey thing is locally available and consider it equivalent. If fungus gnats are a concern, the 100% certain thing to do is water with a mosquito dunk (Bti) as soon as you get started, and you won't get any gnats.
I often see small bags of Promix products in the aisles when our hardware stores get their spring garden stuff out - long after tomatoes are up. But you might find some locally to try on the next round, without breaking the bank on a full bale with shipping. Every gardener seems to have a personal favorite and I guess it varies on specific conditions, how you water, etcetera, so it's nice to try different stuff to see if it works best for you.

[peebee]

@Greatgardens maybe it was too wet? Once it has absorbed water from underneath you can leave it alone for quite a while. I can no longer find the finer texture kind so I'm using what they sell now, coarser grains but seedlings came up just fine. I also use this coarser type to propagate cuttings & it works great.
If you have the small grain type I found that putting a paper towel or coffee filter on the bottom of pot prevents the grains from falling out when they are dry.

[Kingbird]

ProMix is good stuff but easy to make a better version yourself.

1 Part Peat
1 Part Worm Castings (or compost like Coast of Maine Lobster compost) the compost is where your microbial soldiers come from.
1 Part drainage most use perlite as it's easy to find. I LOVE rice hulls. Lightweight (think shipping!), no terrible dust like perlite. Lots of drainage options.

Coco is another great addition and comes in compressed blocks. 2 gallons of water, drop the block in, a few hours later nice fluffy coco. I like adding the coco to peat in order to offset the peat becoming cardboard if it dries out.

1 Part Peat
1 Part Coco
1 Part Compost
1 Part Rice Hulls

This recipe can be modified for whatever stage of growing you are in and be used as an excellent base mix for containers.

To go completely nuts for containers, ah ahem, as I like to do lol, I amend with some great organics.

Basalt
Oyster Flour
Crab Meal
Kelp Meal
Gypsum (water soluble)
Neem and Karanja Cake
Glacial Rock Dust

These are used in small amounts and last a very long time which justifies the extra small cost. The plant's health is just incredible.

Happy growing!

[Tormato]

ProMix is good stuff but easy to make a better version yourself.

1 Part Peat
1 Part Worm Castings (or compost like Coast of Maine Lobster compost) the compost is where your microbial soldiers come from.
1 Part drainage most use perlite as it's easy to find. I LOVE rice hulls. Lightweight (think shipping!), no terrible dust like perlite. Lots of drainage options.

Coco is another great addition and comes in compressed blocks. 2 gallons of water, drop the block in, a few hours later nice fluffy coco. I like adding the coco to peat in order to offset the peat becoming cardboard if it dries out.

1 Part Peat
1 Part Coco
1 Part Compost
1 Part Rice Hulls

This recipe can be modified for whatever stage of growing you are in and be used as an excellent base mix for containers.

To go completely nuts for containers, ah ahem, as I like to do lol, I amend with some great organics.

Basalt
Oyster Flour
Crab Meal
Kelp Meal
Gypsum (water soluble)
Neem and Karanja Cake
Glacial Rock Dust

These are used in small amounts and last a very long time which justifies the extra small cost. The plant's health is just incredible.

Happy growing!

I mostly do starts outside, so I'm at the mercy of the weather. Perfect weather and I can have a tomato transplant ready in 23 days. Awful weather and it can be just over 2 months. When it takes a long time, starter mix that has a pH buffer does better for me, than a mix that doesn't have it. If I mix my own, well measured powdered, quick reacting lime is added. While I've never used it, and I haven't had any for years, I wonder if wood ash would work?

[Kingbird]

Wood ash is excellent for that early P needed. It is just a little too unpredictable for me with young plants. Seems to be a fine line between too little and too much.

23 days is excellent speed to transplant!

[Tormato]

Wood ash is excellent for that early P needed. It is just a little too unpredictable for me with young plants. Seems to be a fine line between too little and too much.

23 days is excellent speed to transplant!

That 23 days has only been done with one variety, Cole, a few times.

Everything else takes at least 28 days. Seeds are sown generally on May 1st in southern New England. With excellent weather, everything is transplanted, over the course of two days, by June 1st. With poor weather, everything is planted by July 1st. And those July 1st transplants are much smaller than the June 1st transplants.

[JRinPA]

Lowe's carried the Promix HP for a couple of years then stopped. I'm now using the Sunshine mix but I don't like it as much, mind you I'm talking about using these in Earthboxes only. I tried those small $13 bags of Promix from Walmart, & they are not the same at all. I would use those in regular pots or in-ground, I believe there are 2 types sold, 1 is a black bag with yellow, the other black with red.

As for seed starting I only use Ultrasorb, the oil absorbent sold in AutoZone or such auto supply stores. No damping off & so easy to separate the seedlings when you do a mass sowing in one container. I would not start teeny tiny seeds like flower seeds(lobelia, poppy, etc) in it though. They'll fall thru the grains I would think.

@peebee or anyone else that uses ultrasorb - can you post a pic of your seed starting trays? I've been reading off and on about DE for seed starting for years. Last year I bought some food grade DE in the garden area at walmart but it very fine and immediately wet out when using it for seeds. It seemed to work okay for dusting for bugs.

[MissS]

Lowe's carried the Promix HP for a couple of years then stopped. I'm now using the Sunshine mix but I don't like it as much, mind you I'm talking about using these in Earthboxes only. I tried those small $13 bags of Promix from Walmart, & they are not the same at all. I would use those in regular pots or in-ground, I believe there are 2 types sold, 1 is a black bag with yellow, the other black with red.

As for seed starting I only use Ultrasorb, the oil absorbent sold in AutoZone or such auto supply stores. No damping off & so easy to separate the seedlings when you do a mass sowing in one container. I would not start teeny tiny seeds like flower seeds(lobelia, poppy, etc) in it though. They'll fall thru the grains I would think.

@peebee or anyone else that uses ultrasorb - can you post a pic of your seed starting trays? I've been reading off and on about DE for seed starting for years. Last year I bought some food grade DE in the garden area at walmart but it very fine and immediately wet out when using it for seeds. It seemed to work okay for dusting for bugs.

I solve this problem by placing a small piece of coffee filter at the bottom of the seed cell before filling it. Or using a small amount of seed starter, vermiculite or worm castings at the bottom of the cells before filling them. This hold the DE in the cells so that it won't pour out of the bottom holes.

[zeuspaul]

I use Ultrasorb which is granular DE, not the powder used as insect control. It looks like clay kitty litter.

I don't use it as a *seed starter* I use it in my seed starter mixes. I use it as a substitute for perlite or in addition to perlite.

Lowe's carried the Promix HP for a couple of years then stopped. I'm now using the Sunshine mix but I don't like it as much, mind you I'm talking about using these in Earthboxes only. I tried those small $13 bags of Promix from Walmart, & they are not the same at all. I would use those in regular pots or in-ground, I believe there are 2 types sold, 1 is a black bag with yellow, the other black with red.

As for seed starting I only use Ultrasorb, the oil absorbent sold in AutoZone or such auto supply stores. No damping off & so easy to separate the seedlings when you do a mass sowing in one container. I would not start teeny tiny seeds like flower seeds(lobelia, poppy, etc) in it though. They'll fall thru the grains I would think.

@peebee or anyone else that uses ultrasorb - can you post a pic of your seed starting trays? I've been reading off and on about DE for seed starting for years. Last year I bought some food grade DE in the garden area at walmart but it very fine and immediately wet out when using it for seeds. It seemed to work okay for dusting for bugs.

[MissS]

@JRinPA You want to use the granular DE that you will find at Auto Zone. The powdered DE is no good for seed starting at all but is very good for insect control.

[JRinPA]

This following wouldn't post around lunchtime: I was working outside all day and didn't get to any starts today, but hopefully tomorrow.
----------------------
I just bought some of that ultrasorb this morning. Through the bag, I estimate it is 1/4 of the nominal diameter of the "luna rock" perlite that I typically use as 25% of my soil block mix.

I planted 6 trays yesterday and varied the way I finished the tops. I will use this ultrasorb on the next flats. It should be a good equal test.

I also am going to start a container of dollar tree lisbon bunching onions in a mass sowing in ultrasorb versus my normal mix.

The pthorticulture website lists Pro Mix HP as ~70% sphagnum peat;
the balance is ~ 30% perlite, limestone, wetting agent, and mycorrhizae

I have started seeds with soil blocks since practically my first year doing seeds, so I have very rarely grown in plastic trays that you fill with dry mix, and then water. I haven't bought any mixes to compare to my standard of 50+% screened sphagnum peat, 25% coarse perlite, 25% screened vermicompost, lime (about 1 tbsp per flat). To that I add an additional 3/8 water, then press blocks. They start out pretty wet and stay that way for days - with a clear lid and bottom heat, seeds generally sprout well before needing to be bottom watered for the first time.

I don't know how well it would work for "regular" plastic insert tray seed starts with loose, dry mix. It does seem that Pro MIx HP at 3 parts to 1 part of vermicompost and 1-1/2 parts water would be very nearly the same thing for my soil block mix.

Does my vermicompost compensate for not having the wetting agent and the mycorrhizae? Or would those two additions make the soil blocks even better?

[peebee]

@JRinPA I can take a pic tomorrow but I don't use seed flats for sowing with Ultrasorb, I do what I think is called mass sowing. So I only have to use any small pot, 3 or 4 in. I cut coffee filters or paper towels to fit the bottom, then I pour the medium in, lay some seeds on top (I usually do 10 to 15 a pot), then add some more grains to cover the seeds. Put the pots in a shallow container of water & wait till the tops are saturated.

That's pretty much it. I grow only about 130 seedlings of tomatoes, peppers & eggplants total so I only need 10 small pots to start the seeds, hence no flats needed. Once they can be potted up I put those individually potted plants in flats to transport them to grow lights, then outdoors about 2 weeks later. I live in SoCal which is why I don't need grow lights very long except at night or when it's cloudy or raining.

Growing in a grainy medium is super easy, I've never gotten damping off which I've experienced before using a peat based mix. And separating the seedlings is easy too, you can either wait till the grains are dry before carefully dumping the pot onto a work surface or if that's hard to do then I just wash off the grains in a bowl of water & separate the roots underwater.

[peebee]

@JRinPA here's a pic of some pepper seeds started in ultrasorb:

20230308_130644_HDR.jpg

@Greatgardens sorry for highjacking your post on Promix. To get back to the subject, like I said I would only use such a potting mix in Earthboxes. Sunshine mix is a substitute but I much prefer Promix which is unavailable now & both products are way too $$ now IMO. If you're just looking for something to use in regular pots there are better products out there, & they already have fertilizer etc in them. I would save time, gas & money buying from a good local nursery or hydroponics store.

[JRinPA]

I take the heat for the hi-jacking!

I'm off right now to start those next trays of soil blocks and some dishes like that with ultrasorb.

I have not seen the Pro Mix HP in any stores, just the red/pink Promix at walmart. I don't know how much it costs around here, but last big 4ft compressed bale of peat was pretty pricey...and also has a lot of rather large wood chunks and sticks. I must be losing between 5%-10% of volume during my 1/2" screening process in this latest bag of "Premier".

Can anyone say, does Promix usually have big sticks or is it pretty well filtered/screened already?

[JRinPA]

I just did some quick checking and there are no distributors listed nearby for Pro-mix HP. Nolt's is my usual garden supply, not close by, but once every year or two I make an order and drive down for pickup because the prices and selection compared to anything around here. Even they don't carry the 70% Pro-Mix HP. They have the BX which is 80% peat and perlite and vermiculite - 3.8cuft bale for $30. $32 for the myco. $33.75 for the myco/bio. They also carry germination mix that is a fine grind 85% peat and fine perlite - 2.8cuft loose for $18.10. For comparison, their Pro-Mix 100% peat moss is $16.80 for 3.8 bale. (there is a price break after 10 bales but is only about 2%)

The last bale of straight peat moss we bought around here was high 20s, last fall. After the last few years, I don't know what "normal" prices are any more.

[JosephineRose]

ProMix HP is my go-to for growing tomatoes in Earthboxes. It has vanished from shelves here - I am concerned it may have been discontinued.

I have checked every hydroponic store around and they all say they cannot get it in.

It's a Canadian product, correct? Has US Ag stepped in for some reason?

[Seven Bends]

ProMix HP is my go-to for growing tomatoes in Earthboxes. It has vanished from shelves here - I am concerned it may have been discontinued.

I have checked every hydroponic store around and they all say they cannot get it in.

It's a Canadian product, correct? Has US Ag stepped in for some reason?

Pro-Mix BX is the same product, just with less perlite. BX is readily available in the DC area, at Ace Hardware and at the big independent garden center near me. I wasn't looking for HP so I'm not positive, but I'm pretty sure I saw it at the garden center on a pallet next to the pallet of BX. HP also seems to be available online right now from various sources.

But anyway, you can just add perlite to BX and get HP. See my other post about ordering BX from Ace Hardware.

[GoDawgs]

ProMix HP is my go-to for growing tomatoes in Earthboxes. It has vanished from shelves here - I am concerned it may have been discontinued.

I have checked every hydroponic store around and they all say they cannot get it in.

It's a Canadian product, correct? Has US Ag stepped in for some reason?

Not a peep anywhere on the internet that I can find as to a reason for the shortage/disappearance. I'm now wondering if the Canadian government is on a "peat sustainability" kick and limiting the use of it.

Edited to add:

I just looked up Canadian peat and thanks to eco-warriors it's a real possibility that Canada is already or will be limiting peat :
https://www.nationalobserver.com/2023/0 ... te-dilemma

This despite that fact that Canada has 200 million acres of peat, 1/4 of the world's supply:
https://www.cbc.ca/news/science/peat-mo ... -1.5411539

Apparently this year England will ban peat sales with Wales and Scotland probably not far behind.:
https://www.theguardian.com/environment ... ed-compost

I ought to find and buy stock in a coir producer because that's what they're pushing as a replacement. That's a ton of coconuts. Hold on to your wallets or find something else. I wonder if the company that makes Pro-Mix is still in business and if so, how long they'll last.