I recently made a huge batch of 5-1-1 container mix in which I used one part coco coir. Then I read about possible sodium issues with coocoir and got an EC meter, and saw that my coco coir reads 1000 EC, and apparently 700 or below is best. That spooked me, so I have since switched to peat moss, however I have already transplanted a lot of fruit trees into the mix with coco coir, and I am wondering if there’s anything I could do to bring down sodium levels in the mix now, after the mix is already made and the trees are in it? I have read that gypsum can remove sodium from media. Would it be a good idea for me to top dress my containers with some gypsum and water it in? Or are you familiar with any other remedies?
The reason I am concerned is I do notice oddities with a few of my plants. I am sending a picture of a mulberry seedling. As soon as I transplanted it, it lost all of its leaves. For a short while I thought it was dead, then it started regrowing leaves at the top, but rather slowly, and notice that while new leaves look nice and green, they quickly turn yellow and get burnt edges. From what I’ve read this is a possible symptom of excessive sodium.
This mulberry seedling was transplanted April 24th, so it’s been in the new mix over a month and still the same pattern of leaves yellowing and withering soon after they grow.
If it is a sodium issue, leach it out with water. It shouldn’t be too hard to leach out. Read the EC of leach water and keep watering until it reaches the desired level.
I mixed osmocote in with the mix and also dr earth alfalfa meal, and more recently I started doing liquid fertilization with growscripts, so I think it should be getting enough nutes, especially given it’s a young plant? But what if for some reason it isn’t able to take in the nutrients? That’s one reason I was wondering about sodium because apparently it can lead to nutrient lockout?
The other thing I’m wondering about is maybe my mix is retaining too much moisture? could that cause leaf issues like that? whenever I test it with a wooden skewer, the skewer comes out with moisture on it. so it doesn’t seem like my mix is drying out much. I am in socal, 10a, and the weather here has been cool and gray almost every day, we aren’t getting a lot of warm sunny days - could the lack of warmth be leading the mix to maintain too much moisture too long?
Seems like maybe overfertilization. I just looked up grow scripts. It looks like it’s super concentrated. 5-1-1 mix is highly unlikely to retain too much water.
Yes, pour water on the top and drain it out the bottom. Collect the drain water and test the EC. I have a horse pen that I now have planted to fruit trees. I had to leach about 12 inches of water through it to get sodium levels low enough to grow trees. Horses get salt licks and it builds up in the soil from the lick and urine.
Okay I’ll give that a try. I’ve got nothing to lose! What are the EC levels I should know - what EC represents too much sodium and what EC to know I’ve got it to a good level?
My horse pens tested 6300 umho/cm (rated very high). Other areas were 250 (rated none) to 1350 (rated moderate). I guess you are using the same units so below 700. But I’m no expert on what’s okay and what isn’t.
About ten years ago,I attended the International Plant Propagators Society’s Western Region Annual Meeting
There is some info in there about your question,because a big grower of container plants,Duarte Nursery,uses coir and they clean and buffer it themselves.
So,in addition to pouring water through,basically Calcium Nitrate is used to buffer.I’ve read dolomite lime can also be used.Soaking with some Epsom salt and Calcium Nitrate is also done.
