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gauge17

Use Al's Gritty Mix or river silt?

Gauge17
10 years ago

With my situation, should I use Al's Gritty Mix, river silt, or something else entirely?

Here is my setup. I have what l call an "in-ground planter" (no idea if that's proper terminology). It's a 4 foot by 4 foot square opening in my patio (I just finished building the patio and the in-ground planter). The bottom of the planter is completely open to the earth beneath. The sides of the planter are made of pressure treated 2 X 10's, which separate the interior of the planter (on the sides only) from the crushed rock sub-base of the paver patio. It's about 20 inches from the top surface of the planter down to the natural, native soil beneath (which is clay that doesn't really drain at all). In order to keep the in-ground planter from filling up like a bathtub, during construction I installed a drainage system at the bottom of the planter (it's basically a french drain that slopes down to the lake which is about 75 feet away). So, in my amateur opinion, the in-ground planter has some characteristics of a container for potted plants, and some characteristics of a raised flower bed in the yard. I also installed an automatic irrigation system into the planter, so I'm able to water it as frequently and with as much water as I want/need.

About a month ago I filled up the planter with Miracle Gro Cactus Palm And Citrus Soil - since I assumed it was probably the best stuff for my purposes and would drain very well (after reading this forum for the past few days I now realize that this soil probably wasn't the best choice). I then planted a majesty palm in the center, and surrounded it by water loving tropical plants that need to be watered twice a day. I set the irrigation system to water twice per day. A month later and the tropical plants are doing well, but the palm leaves are starting to turn yellow from what I'm pretty sure is over watering and the soil being constantly soaked.

So, I'm about to dig all of the Miracle Gro soil out and replace it with something else - hence my question.

I intend for the palm to live in this same spot for at least 10 if not 20 or more years just like it would if it were planted in the yard, so replacing the soil every few years is not really an option.

In view of this, it appears that I need:

1. a soil that is very well draining and that almost can't be over watered, thus allowing me to water the water loving tropical plants twice per day without also drowning the palm and/or the less water loving plants that I may also plant in the planter in the future; and

2. a soil that will hold up for many years (as in 10 to 20 years) and won't break down and become soup over time (like, as I understand, off the shelf potting soil will).

After some reading, it appears that Al's Gritty Mix may be what I need, but I'm not sure. I have at least two concerns (feel free to tell me if there are other concerns that I haven't thought of). First concern is will the Gritty Mix hold up for this length of time. I know it's supposed to be good for several years, but what about 10 to 20 years or more? I need the soil to basically last forever just like the soil that the canary island date palm that I have planted out in my yard will. Second concern is fertilization. In the beginning, the entire point of putting in the automatic irrigation system was to make the planter as low maintenance as possible, so I don't want to have to fertilize with a water soluble fertilizer ever day or even once per week. I would like to be able to just fertilize with something like a controlled release fertilizer ideally no more than once per month - if not less.

In short, I need a well drained soil that almost can't be over watered, will basically last forever, and that doesn't need to be fertilized more than once per month. Will Al's Gritty Mix work for this? Instead do I need something like river silt that is more permanent and won't break down over time? Do I need something else entirely?

Sorry for the long post, but I would really appreciate any suggestions.

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