I did a search for Mycorrhizal Fungi and all I came up with was a very old post in the Off Topic forum. I thought that was odd as on a Banana forum there are quite a few posts about this. One even spoke of how Citrus really need them. I understand that all trees have fungi that their roots form relationships with but do Citrus in general have a special need for them? Does anyone here use a particular brand? Are any of them specialized for Citrus? How do you inoculate the soil?

The entire issue of mycorrhizae is an interesting and complicated one. Yes, citrus have an absolute requirement for them, and it has been postulated by researchers that they could not be healthy without them, particularly from chronic phosphorus deficiency, even if heavily fertilized with phosphate.

On the other hand, with citrus, as with nearly all (perhaps absolutely all??) other plants, there is no evidence that commercial mycorrhizal formulations do much if any good. The reason for that is that the spores are air-borne, in the dust, and so they are constantly being transported all over the earth. Wherever they land, if the soil conditions are right, they grow; if the soil conditions are not right, they don't grow. So if you have a soil that is amenable to a particular strain, that strain will almost certainly already be there, at maximum concentrations that that soil will support. Adding more is a waste.

The only situation in which addition of a commercial product may be useful is on recently sterilized land, or potted plants potted into a sterile potting mix. In those cases, immediate addition of the commercial stuff can bring the population up quickly, rather than waiting for enough spores to land and grow naturally, which may take weeks or months (but not years). So even there, you might get a benefit for a few weeks on citrus, but in the long run, no added value. With a short-term crop like annual vegetables, you may see a much larger effect, just due to the time involved.

If you buy a citrus tree already in a pot, it has almost certainly been growing at the nursery for several months; perhaps more than a year. If it looks healthy at the time you buy it, you can virtually guarantee that its root system already has a healthy flora of the proper mycorrhizae. Addition of more at or after planting time will not likely have any noticeable effect.

Wow! What you said makes a whole lot of sense. It is certainly controversal to what everone else is saying but entirely logical. From my limited knowledge on citrus it appears that they do not like a heavy humousy soil but one that is a bit more to the sandy side but still fertile. I guess that my soil on the sandy side with the addition of some compost will probably be fine and since I have a large grapefruit tree nearby the spores are available just waiting for a host.

Thanks,

Darkman, is your above post about planting a citrus tree outside in the ground? - Millet (881-)

I would not add compost nor any other soil amendment, if you're planting outdoors, in open soil. At most, add something for pH control (e.g., lime if your soil is too acid; likely in Pensacola).

Millet - Yes it is outside.

Malcolm Manners - I would not add compost nor any other soil amendment, if you're planting outdoors, in open soil. At most, add something for pH control (e.g., lime if your soil is too acid; likely in Pensacola).

Really. I was planning on discing the ground about 10' wide and then removing all roots and adding a compost to the entire thing. What would you do. This is virgin open land that had some small trees and wild grass maybe Bahia growing.

Thanks,

Darkman, the reason I asked if the tree was going to be planted outside in the ground, was because if it was to be an outside planted tree, I was going to tell you exactly what Dr. Manners has already written above. Dig a hole just large enough to comfortably hold the root ball, and back fill only with the soil you removed to make the hole. Then make a water basin that will hold approximately 5-gallons of water so you can water the new tree. Do not dig a big wide deep hole, as you will be making a lake for the roots to drown in. Good luck with your tree. - Millet (880-)

It seems that Citrus do not like to be pampered. Is this right? If you were going to clear twenty acres of lightly wooded ground, what would you do? Would you just clear it all and then prepare the holes as you have said above? I don't have twenty acres but I am planting an area 80' by 50'. It will be about 60% Citrus and I want it to have everything it needs to have a good start and develop a solid root system. That is why I was planning to disc the whole area remove all stumps and roots. I thought that the disced ground would be equal everywhere and be a good start for all the trees. You are saying that I am doing unneccesary work? Right?

About the compost, it is confusing to me as I have always been told that everything benefits from compost. I'm not talking about mulch and the compost would be worked into the entire area not just around the root zone. Until the trees get larger I will plant rows of vegetables in between the trees I will stay far enough away that I don't damage any roots. As long as the compost is well distributed would it still be a bad thing?

Thanks,
Charles

The most productive citrus land in the world is in Highlands County, Florida, near Lake Placid. That soil is a very light sand, often with less than 1% organic matter and seldom as much as 5%. Yet mature trees on a vigorous rootstock can AVERAGE over 1000 boxes (90,000 lb, 45 tons) of fruit per acre, year after year.

Trees don't grow well on so-called "sand sink" or "sand pond" areas, where the sand is pure white and consists of almost nothing but silica, but our other soils, which are very predominantly sand with just a bit of clay, can grow very good citrus.

Certainly, there are good trees on more organic soils as well (in the Immokalee area, often in muck, which is nearly 100% organic), but they don't grow as well or produce as much, there.

If you're planting a containerized tree in mostly organic media into the open soil, which is predominantly sand, I'd add a step to Millet's advice: shake/wash as much of that organic media away as possible, creating a nearly bare-root tree (don't let the roots dry out, and don't break more of them than you have to in the process). Then hold the tree in the hole at the proper height (a shovel handle thrown across the top of the hole will remind you of how high the soil level is, at the center of the hole). Hold the tree a bit higher than it was in the original pot -- you'll want to be able to see a few roots above ground when you finish.

Fill the hole with water. Then add soil, a handful (or shovel full) at a time, working it around the roots under water, thus working out all the air pockets that may be there. When you finish, the land should be at the same level as it was before the operation began, and the trunk of the tree should show a few bare roots near the surface.

Then as Millet suggested, I like to make a water ring around the hole, to enable easy watering.

If you simply put a mostly organic root ball into a sandy soil, every time you water, the organic material will swell, then as it dries, it will shrink a bit, creating a recurring crack between it and the surrounding native soil. That crack tends to inhibit roots from moving out into the native soil. I've seen trees planted that way, dug up 5 years later because they appeared to be severely stunted, to find that the roots had hardly left the original root ball. By baring the roots and getting them immediately into intimate contact with the sandy soil, you solve that problem.

OK I'm sold. It is just so hard to except that easier is better. LOL But I'm glad to hear that the planting phase of this is going to be a lot easier and cheaper than expected. I'll just concentrate on getting rid of any competeing roots and Vegetation. I'll have full sun here and in the end I should have a nearly perfect spot as you could ask for in NW Florida to plant citrus.

What time of the year would you recommend for planting if I wash the potted soil off the plants prior to planting. Fall, Winter or Early Spring?

Thanks,

Well, if you can stand to wait, probably spring, after danger of frost.

Spring is fine and will probably be best for me as I am still clearing the land. After work today I cut down three large trees and five small trees. As a bonus the tops of the trees were covered in wild muscadines which we gratefully ate. They were very sweet and juicy although they are a bit on the small side and seedy. Almost sounds like some of the Citrus y'all describe here.

Thanks,