modified 5-1-1 mix for acid loving plant (Miracle Fruit)

12 years ago

I recently got a small miracle fruit tree, and would like to move it into a larger pot. These plants need very acidic soil, so I was thinking of using Al's 5-1-1 mix, but using gypsum instead of lime. Sound good?

Alex

Featured Answer

tapla (mid-Michigan, USDA z5b-6a)

12 years ago

FWIW - I wouldn't use any sawdust in a container medium unless it was redwood.

It's very difficult for hobbyists to control the pH of the medium proper, but easy to control the pH of the soil solution, which is much more important, by simply adding enough white vinegar or citric acid to a given volume of water to lower the water to your target pH. Record how much acid it took and add that volume to your volume of irrigation water each time you water.

Comments (8)

redshirtcat
12 years ago
You will need a source of magnesium (epsom salts periodically when you water/fertilize)
roachslayer
12 years ago
I have a miracle fruit plant growing very well, fruiting right now. It is in a mix I _THINK_ of 4-4-2, Peat/Perlite/bark fines. In other words, VERY acidic due to large peat. The perlite is critical for drainage when using so much peat.

I'm not sure 5-1-1 is going to be low enough acid. Peat is more important than gypsom, but yes, you should could add gypsom and then epsom when watering.

Look at what folks are doing for Blueberries - they share similar pH requirements. My blueberries are in a 4-4-2 mix of Coir/Peat/Perlite - also very acidic, and I am considering this mix when I transplant my miracle fruit.

If anyone has better ideas, awesome.

I'm also using MirAcid for fertilizer just to be sure its getting something, but only until I determine what organic food to give it.
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calistoga_al ca 15 usda 9
12 years ago
Gypsum does not affect the soil PH, so it would not make the mix more acid, but lime would make the mix more alkaline. Al
roachslayer
12 years ago
Sulfur may be a good idea. I forgot to say that in my 4-4-2 for blueberries, I mixed in 1 handful sulfur granules per plant. This is very slow acting, but should help maintain low PH over time (years).

My understanding is that gypsum is useful for leeching out salts (good if using CHC) as well as adding calcium, and helping maintain nitrogen. Since this raises pH a bit, I countered it with Sulfur for low pH requirements (blueberry, miracle fruit).

I took a second look at this link:
http://www.specialtycrops.colostate.edu/scp_exp_demo/blueberries.htm

Miracle Fruits likes pH of 4.5 - 6, and blueberries just a bit lower range - which is why I used that as a reference point.

So this means the 5-1-1 mix might be ok for pH, especially if adding sulfur as I mentioned. I will have to look into this more now.

Watering:
-use 1/8 to 1/4 tsp Epsom at each watering
-use low pH water (add 1tsp to 1Tbl vinegar per gallon if needed)

Here is a link that might be useful: Blueberries in Pots project (ideal pH)
alexander3_gw
Original Author
12 years ago
Thanks for the feedback. Maybe I'll increase the peat a bit, and be sure to add a wick to the pot.

Alex
roachslayer
12 years ago
Confirmed: 4-4-2 Peat/Perlite/Bark is the way Pine Island Nursurey plants their miracle fruit.

My guess just from looking at mine I got from them was spot on. :) And actually, they said "sawdust" not bark, but I would probably stick with bark for my own mix.
ykerzner
12 years ago
Roachslayer - elsewhere on Gardenweb there's a discussion on how to make soil more acid. A story is told that some guy regularly mixed sulfur into his garden to lower the pH, but it took 20 years for the pH to go down by one unit. Given the properties of your mix the sulfur will be washed out of it so quickly it won't even begin to have an effect.