My first Gritty Mix and screening (how-to pics)

12 years ago

Hello all--

Well, I finally did it. After reading about Al's Gritty Mix for the last two years, today I finally got up the motivation to track down the supplies and make some for myself.

Some other posters have previously expressed intimidation at the prospect of beginning the Gritty Mix process. Let me say that I shared this initial intimidation, which is probably why I waited so long to make Gritty Mix of my own. In the end, however, I'm glad I undertook this task and I look forward to it paying off with my plants.

In this thread I want to detail my personal experience with obtaining the Gritty Mix supplies and actually making the mix. I hope that some of the more experienced forum members will be able to identify any mistakes I made or supply helpful hints as to how to go about the process more efficiently in the future. I also want this thread to serve as somewhat of a how-to for those that are toying with the idea of making their own Gritty Mix, in effect de-mystifying the whole process. I wholeheartedly invite commentary and suggestions from anyone interested in this subject.

I began by locating the mix materials (see pic): crushed granite, turface, and fir bark. I'm happy to say that I was able to find all the materials in my vicinity. That is not always that case, however, and there are other threads that discuss different substitutes for these materials if they are not available in your area. I myself just moved to RI from GA, so finding these materials was a good exercise in getting my bearings in RI/MA.

{{gwi:48076}}

Crushed granite -- I found this at a local feed store for use with poultry. It's called Gran-i-grit as you can see from the pictures. I made sure to examine the particle size before buying (see pic). I looked for Manna Pro brand, but only found Mount Airy. I don't think the brand matters at all. I got a 50 lb. bag for $10.

{{gwi:48077}}

Turface -- I found this, like many other forum members, at a local John Deere Landscaping store. A 50 lb. bag sold for $17.

{{gwi:48078}}

Fir bark -- Al discusses pine bark fines in his post "Container Soils: Water Retention and Movement", but many have used fir bark with good results and it was really easy to find fir bark at a local Petsmart. It's called Reptibark and it comes pre-screened in 24 qt. bags which sell for $12, if I remember correctly.

After I had gathered these materials, I went to Lowe's to buy the supplies to make a screening basket. The idea here is to wash your mix materials to eliminate dust and small particles which will retain too much water, defeating the whole purpose of the Gritty Mix. Here's what I bought at Lowe's:

--1 pine board (2x4x10) cut into 4 equal pieces (30 in. each)

*In retrospect, I probably only needed a 2x4x8 board

--8 three-inch wood screws

--Aluminum screening (found in the door/window section)

All of this cost me $14. I already had a staple gun and drill at home, but if you don't, you'll need some way of connecting the boards and screen.

Then I went home and assembled the screening box (see pics). This was a very simple process and anyone could do it.

First I assembled my materials:

{{gwi:48079}}

I then used the wood screws to secure the planks to each other, making a perfect square:

{{gwi:48080}}

I then laid out my aluminum screening and cut off the right amount. The screening basket will be stronger if you wrap the screening around the sides of the basket:

{{gwi:48081}}

This shows the gauge size of the screening:

{{gwi:48082}}

I then used my staple gun to secure the screening to the wooden box. Be sure to make the screen as taut as you can:

{{gwi:48083}}

When you're finished, you're left with a screening basket:

{{gwi:48084}}

As I currently have very little outside space, I chose to do the screening in my bathroom. I somehow convinced my fiancee that this was necessary, but, in the end, I probably won't do it that way again. It wasn't overly messy, but there is certainly that potential and if you can do it outside or in a utility sink, that would definitely be preferable.

I used a 2-qt. pitcher to keep my ratios (1:1:1) correct:

{{gwi:48085}}

I set my screening box upside-down across my tub. I turned it upside down because it can hold more weight that way and because it made it easier to transfer the screened material to a plastic tub that I had placed underneath:

{{gwi:48086}}

I then laid out 2 qts. of Turface and 2 qts. of crushed granite on top of the screening basket. I chose not to screen the bark because Reptibark comes pre-washed but other barks might need to be screened:

{{gwi:48087}}

{{gwi:48088}}

The basket easily handled the weight of these materials combined.

Then, using my movable shower head, I began rinsing the materials and working my hands through them to aid the screening process.

Here is a pic of the dust and fine particles you're trying to get rid of during screening:

{{gwi:48089}}

*Note: Don't let these particles go down your drain! I used some surplus aluminum screen to cover my drain.

When I was done screening one round, I was too impatient to let it dry, so I transferred it damp into a plastic container.

{{gwi:48090}}

I'll be using this mix in the next couple of days, but if you plan on storing for long periods, the mix should be allowed to dry.

I then added equal parts of the fir bark and my mix was complete! I was left with a decision to make: which plant to re-pot first. I sought out the Gritty Mix materials specifically for a ficus b. that desperately needs repotting, but it was getting late and I thought I'd save that for tomorrow. I settled on a strange little bald cypress tree. This tree was trunk cut for bonsai-ing 2 years ago, but I haven't had the time to devote to bonsai so I just let it grow out and I now like its unusual appearance. I need to do some pruning around the trunk base, but I'll take care of that tomorrow.

Anyway, the only ceramic pot I had available was a little too small for this specimen, but I thought this would be a perfect opportunity to practice root pruning, another thing I have long feared. I took the cypress out of its nursery pot and gently began working away the soil. When I had worked most of it away, I got the hose and washed the rest off. Unfortunately, I forgot to take a picture of the root ball before pruning but this is what I was left with:

{{gwi:48092}}

{{gwi:48093}}

I'd say I removed about 40% of the total root structure.

I then proceeded to pot it in the Gritty Mix and this is how it turned out:

{{gwi:48095}}

{{gwi:48096}}

The only thing I'm concerned about is the root coverage. As I said, the pot I transferred the cypress into was a bit too small, so I'm considering taking it out again in the next few days and do some more root pruning. I think this cypress wants to extend its roots, so a more severe root prune might be in order if I'm going to keep it in this pot.

Is it okay to leave a main root hanging out like that? It king of looks cool, but I certainly don't want to keep it that way if it's not healthy for the plant. Suggestions?

I have a lot of fig trees, succulents, and other houseplants that I can't wait to transfer to the Gritty Mix in the next few days!

Questions:

--I know gypsum was in the original Gritty Mix recipe. Is this something I can add later?

--Is it advisable to use a generic water-soluble fertilizer with plants in the Gritty Mix? Any other suggestions regarding supplements?

So far this has been a rewarding and promising endeavor and I encourage those of you considering Gritty Mix to go for it! It's really not that hard and it's all a learning experience.

Feel free to respond with comments, suggestions, alternative techniques, or feeding tips.

Buena suerte!

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Comments (16)

Loveplants2 8b Virginia Beach, Virginia
12 years ago
last modified: 9 years ago
Hello tcleigh,

I must say that i'm very impressed with all that you have done...

BRAVO!!!

You did a great job in collecting all of the great ingredients and putting together the screens as well!!

How in the world did you get your fiancee to agree to this in the bathroom? LOL You have a gift to be able to do that!!! I dont even think that i would do that in my bathroom...your bathroom looks so beautiful too! : )

I love everything that you have done and i have to say that you went right to town.

Pretty work!!!

As far as some of your questions about the roots etc.

I will let someone else with more experience add to your post and answer those questions!!!

I just want to say that you have done a great job!!!

I like to use Foliage Pro for fertilizing. You would probably like it as well. Sometimes it is hard too find, but you can alwyas find it on line...

Good Luck!!!

Laura in VB
calistoga_al ca 15 usda 9
12 years ago
last modified: 9 years ago
Well you are certainly a detail person. I am sure all your details will help anyone contemplating making a mix for the first time. My only suggestion, based on my need to screen a variety of materials, would be to fasten the largest screen size to your frame, (also the strongest)cut out whatever number of smaller size screens needed, to insert on top of the permanent screen as the job requires. Al
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1) The mismatched sizes, if a problem, will cause separation of the ingredients (the smallest particles will go down toward the bottom, leaving the bark pieces near the top). This will happen over time as watering is done. If the sizes are truly screened (correctly) over the insect screen, this won't cause a PWT but it will make the top portion less water retentive. So it will feel drier in the top and the upper roots MAY die off, but create new ones down below. In your area, the separation may not be of any significant concern -- esp. if you put a mulch on top (like larger granite rocks). If I start noticing this, I usually sprinkle more Turface on top -- but I live in arid Central CA so I need more retention on top anyway and always use some kind of mulch. The issue with undersized grit can be a concern. The smaller size is what I use, but again I'm looking for more water retention. The fact you shorted the granite may compensate for the undersize. 2) Larger grit pieces (the size of the largest screened Turface or a bit larger) are great for indoor plants or work for outdoor in locations with higher humidity and/or less direct sunlight (daytime hours). 3) Probably not soaking the bark -- it will repel the water at first. I wouldn't sweat it. This is normal to get freaked out about how little water is retained. Yes you water more often -- but SO much less qty is required. The gritty mix isn't wasteful of water, so don't feel like you need to drench it everyday. It won't hurt, but it's not required once all your bark is wet. Gritty mix IS wasteful of fertilizer though due to frequent watering. 4) No. Let the water drain out, especially in your area. 5) Sprinkler is much much better, but once your bark is saturated the first time, it's not a big deal. But if you pour, you MUST pour evenly around the entire mix area. You can't just pump it in one spot and let it diffuse through the entire container like "we" did with typical bagged mixes. 6) I haven't read the thread. Ignore the specifics of what others are saying and just learn from the generalities. They aren't living in your area, using your containers inside your microclimate, nor having the same plants in the container. If your container is large enough, so there is plenty of room for roots to grow into (like a few extra inches around the sides past the roots placed outward) than you'll be fine for now. It becomes a problem when your roots take up the entire root zone.... 7) Yes the roots should have been spread out. They don't have to be layed out completely flat (saucer like) but they should've been at least like a cone -- not straight down. It was even MORE important that you carefully put mix in between the roots. I hope you followed those directions. You have to flare the roots out horizontally, but also spread them vertically so there is gritty mix between them. You'll get some that don't like the barerooting -- which may have been your fault ;-) or the type of plant or a quirk. Just be sure they are in partial shade for a couple weeks out of the hottest sunlight of the day. Overall: If you are planting fruit trees in outside containers, this should be fine. Especially when they start to fruit, you'll want the extra water retention. I know NOTHING about herbs, though. I wouldn't worry too much yet, but next time you might want to just do a 3 at a time to get some experience and wait a couple days before starting the next. If things start going downhill, it may be due to the root placement within the mix (non-flared and not spread within the mix vertically). If this wasn't done correctly, yes you could lose some times of plants. Hope it goes well -- got any pics of how they look now? If I don't reply directly and you need more help, I'm sure others will chip in. But if not, you can email me directly.
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mksmth zone 7a Tulsa Oklahoma
12 years ago
last modified: 9 years ago
wow Id have to bath outside if I did that to our tub. Looks like you did a great job. Leaving that root exposed wont hurt a thing. It will just grow bark like the rest of the trunk. I kind of like the look of trees that have a root like that. Makes it look well anchored down.

mike
tapla (mid-Michigan, USDA z5b-6a)
12 years ago
last modified: 9 years ago
Great job on the details.

A couple of points - I screen outdoors on breezy days and I don't use water - I think it's easier and faster ..... and you don't need to let the soil dry. I also measure the 1:1:1 ratio of ingredients AFTER they're screened. That's just what works for me, but whatever gets the job done & you feel is easiest is what's best. ;-)

Initially incorporate gypsum and use Epsom salts regularly in small doses IF you're using a soluble fertilizer (like Peters/MG/others) that DOESN'T contain Ca and Mg. If using Foliage-Pro, skip both Epsom salts and the gypsum - it's in the fertilizer.

Pot size is fine, but I'm not sure the timing was the best. I'd repot (it's Taxodium distichum, yes? - bald cypress) it in the spring before serious bud movement. It WILL fill the pot with roots quickly, and that will limit growth, so if you want to max the mass, go with a bigger pot ion the spring & repot yearly.

I would remove what was formerly the trunk growing under the adventitious roots that sprouted from the trunk at the next repot. Keeping your root system shallow makes it easier to tend. In the picture of the roots where your hand is showing, I would sever the lower trunk just below where the dark (black?) marks on the trunk end - just below the attachment point of the main grouping of roots.

Your figs/succulents/houseplants are going to love it. Once you get the watering down, you'll be on easy street. ;-)

Good luck - good job!

Al
imstillatwork
12 years ago
last modified: 9 years ago
Your strange little cypress is.... wait for it...
...a Coastal Redwood... :)
margo_k
12 years ago
last modified: 9 years ago
Very nice job! Looks like you have a very fine gritty mix. Your plants will enjoy it very much. Good work on making the screens too. They should be veryhandy for screening the ingredients.

As Al would say, "strong work". :)

Let us know how your redwood tree does in your new mix.

Margo
tcleigh
Original Author
12 years ago
last modified: 9 years ago
Thanks for all your responses, everyone! I'm very excited about potting more plants in the gritty mix after this hurricane departs.

As far as fertilizer goes, I think I'll order some Foliage-Pro so I can get nearly all my nutrient requirements in one place.

Al -- that's good advice about screening. Seems like a much less labor-intensive system than my tub method. Regarding the trunk/roots, I had a feeling I didn't take enough off, but I didn't realize I could chop off the old trunk altogether. That will certainly help keep things shallow and easier to maintain in the same pot.

imstillatwork -- I have to respectfully disagree with you on that one. Might you be biased based on your location? :) I purchased that little guy from a landscape supplier in GA. He, in turn, had bought all his saplings in FL, where the bald cypress is king. I grant that they look very similar when they're small, but if you compare various pictures, I think you'll realize it's a bald cypress (or maybe the pictures aren't detailed enough).

I kind of wish it was a Castal Redwood, though.
meyermike_1micha
12 years ago
last modified: 9 years ago
Now that the electricity is back on I had to look at this thread.

Bravo, BRAVO!

Mike
greenman28 NorCal 7b/8a
12 years ago
last modified: 9 years ago
Great job!
Looks like Bald Cypress bark to me, too!

Josh
tapla (mid-Michigan, USDA z5b-6a)
12 years ago
last modified: 9 years ago
One last hint, though it's probably a little late. 1x4 lumber will do the job very well @ half the weight of 2x4s. That will become more relevant when/if you start shaking the sieves to screen out fines.

Again - good job on the details - wish you much success.

Al
anitamo
12 years ago
last modified: 9 years ago
Thank you for your pictorial, it's so helpful.
I'm in the camp of confused right now about the gritty mix, but do want to understand it all. I understand the mechanics, just not where to purchase the ingredients. I wish there was a store called "Al's Gritty Mix Market." LOL. So it would be a one stop shop. Thank you for your pictorial, it's so helpful.
monet_g
12 years ago
last modified: 9 years ago
Anita,
I see that you're in IL. "Oak Hill Gardens" (outside of Chicago) carries the small bark for the gritty mix. After Al recommended it, I got a bag the next time I was in the area.
Gail
User
10 years ago
last modified: 9 years ago
Many thanks for this wonderfully illustrated and informative post. Like you, I have spent the last few months (not quite two years, like you) reading about the gritty mix and more importantly the fundamental concepts. I feel like I have gotten a rudimentary grasp on the core ideas although I certainly still have much to learn. However, as a beginner to container gardening in general and soils in particular, I found myself lacking the practical techniques to put those ideas into practice. Your post has definitely given me the tools I needed to set out on this path and you have my sincere thanks!

Nathan
Need2SeeGreen 10 (SoCal)
9 years ago
last modified: 9 years ago
Hello!

I hope this isn't rude to piggyback, but I just had a couple questions about the screen size.

I thought in the original direx for gritty mix, it said this (I'm not putting in the bits about fertilizer, just the particle stuff):

"1 part uncomposted screened pine or fir bark (1/8-1/4")
1 part screened Turface
1 part crushed Gran-I-Grit (grower size) or #2 cherrystone"

Now, did that mean that we want all 3 ingredients to be between 1/8 and 1/4 inch?

Or are there different sizes for the other 2 ingredients? Because somewhere on one of these threads, someone asked if it should be screened so that you have "1/8" screen for grit and Turface and 1/4 for the pine bark?"

Which confused the heck out of me. We want them around the same size, I thought.

Again, apologies if this is rude. It's just that every time I think I'm getting close, I realize there's some other really important and complicated aspect I don't understand.

Once I get this particle size business down, I'm going to go with some sort of bark/DE thing, and just hope for the best. (At least, I think that's what I'll do. Can't have a heavy mix. Need lots of water retention.)

Well, I hope this wasn't obnoxious. These screen how-tos are fantastic!!! I had thought it would be too hard but this makes it seem doable. So, thank you!!!
oxboy555
9 years ago
last modified: 9 years ago
Yep, all around 1/4". Gritty with all ingredients at 1/4" is an awesome mix.

That said, you don't have to get all OCD about it to make a nice mix.
Screen the Turface over bug screen or 1/16" at the very least. You really want everything over 1/8"....no powder or fine materials.

Um, your penultimate paragraph is confusing. Gritty is heavy in terms of raw weight, but light in terms of draining. If you want major water retention, why on earth start with Gritty materials? Having a light-draining mix and excessive water retention are darn near mutually exclusive.
Need2SeeGreen 10 (SoCal)
9 years ago
last modified: 9 years ago
Thanks for your response! If I sound confused, it's probably because I am. ; >

F.e., I don't understand what "light in terms of draining" means. Does that mean it is fast-draining, such that it lets the water out quickly? I hope it is not *too* quick.

At any rate, I am trying to use a lightweight version of Gritty Mix (by using DE and bark 1:1 instead of using any grit ...) for two reasons: 1) I want my mix to last, and 2) it needs to be light as possible because I garden on a balcony.

I need something water retaining b/c it gets extremely hot on the balcony. (I do see that water retention and lightness are at odds -- but that's just reality... right? Anyone got ideas?)

It's true I could just do 5-1-1, but I may not be able to re-pot as often as I should, given limited time and resources. (I assume DE is heavier than bark, though come to think of it, I don't know for sure. Stands to reason though.)

Unless everyone here tells me the 1:1 plan doesn't make sense, for some other reason?

My first Gritty Mix and screening (how-to pics)

Comments (16)

Loveplants2 8b Virginia Beach, Virginia

calistoga_al ca 15 usda 9

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My first Gritty Mix and screening (how-to pics)

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