When container citrus growers over waters their trees, the chance of the tree's roots becoming rotted, causing damage or death, is greatly increased. It is not actually the over watering that causes the damage, it is the lack of oxygen to the root system, that eventually kills the tree. In older compressed and slow draining growth mediums the water displaces all the oxygen from the medium, thus suffocating the tree's roots. Yes, roots need air too. I selected 42 of my containerized citrus trees that were growing in either 4 parts 1/2-inch CHC and 1 part peat moss; or 3 parts 1/2-inch CHC and 1 part 1/2-inch perlite along with 1 part peat moss. Both of these mediums provide excellent drainage, and exhibit outstanding aeration. Starting June 15th, I begun to water all 42 trees every single day. On a few days I even watered some of them twice a day. I added a weak fertilizer solution every other watering. Today August 1st, is the 48th day in a row, that the trees have been watered. All 42 tree are in excellent condition and have put on new flushes of growth. This demonstrates the fact that when a medium provides good root aeration on a continuous basis, an over (vast) amount of water that is applied causes a problem. I will continue watering through out the summer month of August. - Millet

Very interesting! A good experiment.

Mother Mature has been conducting a similar experiment on my containers--it has rained pretty frequently here over the past month at least. I believe it is the excellent aeration I get from the large pine bark chips that has prevented me from having any problems with my seedlings in containers.

That brings to mind another reason to avoid organic fertilizers for container citrus-- to make the nutrients available, the organic fertilizers must be decomposed by bacteria--using oxygen in the process.

Interesting Millet - thanks. Quite a while back I mentioned something on this forum that I do at the nursery that seems to fly in the face of the overwatering idea. Most of my citrus are in an area where I carefully regulate water to prevent root damage. Many plants do better with more water, so I have another area that receives more water. Right now that area gets water twice a day. In the more heavily watered area, I have community pots of citrus rootstock seedlings. The area is partly shaded and the seedlings seem to like the light there better. Despite the added watering, they never suffer from root rot and, in fact, they seem to thrive on the extra water. When I divide them for repotting the roots are healthy, as are the plants. I have never known for sure what causes them to take the extra water without root damage. I have wondered if it might be that they are getting so much water that the extra water somehow keeps the potting media oxygenated, similar to plants that are grown hydroponically.

Ned

Ned the blend of growth medium that you use, has good drainage and good aeration. Citrus roots cannot even absorb water without soil oxygen present in sufficient quantities. Roots require oxygen in order to do their work. I've seen the medium you use in your container stock, as I have purchased some of your trees. It is heavy, but the drainage is very good. I can see why you are not having root problems. - Millet

What is CHC? Interesting.

Interesting experiment Millet. Just curious, what is your "normal" watering time interval is for this media?

CHC is a common abbreviation for Coconut Husk Chips. CHC is the ground up brown hard shell of coconuts. Commercially, the coconut shell is ground to various sizes: 1-inch, 1/2-inch, 1/4-inch and powdered. The powdered is called Coir, and is used much the same as peat moss. Brad, normally, I water the containers as needed, depending upon the season of the year. CHC hold up to 7 times their weight in water, and being chips still provide excellent aeration to the roots. Another benefit of CHC is that the pH is naturally 6.5, exactly the perfect pH for citrus. I would say CHC's largest draw back is that they make a light growth medium, so trees in small containers setting outside during the summer tend to be blown over by the wind. Therefore they need to be anchored in some manner. A good method to prevent this is using pot-in-pot. Bury a slightly larger container in the soil, and then set the tree's container inside it. This method also prevents the root system from being over heated by the sun's rays. All of my trees are inside a large greenhouse, so I don't have a wind problem. - Millet

Thank you. This is a product we dont have here. Few nursery sell citrus trees.

We have had a few days without rain and my trees are showing signs of being dry--leaves curling, drooping a little. I know the trees do not need water--I have seen this before after sustained periods of rain. I think this response is what gets a lot of beginners in trouble, the trees are use to lots of water and high humidity, when that stops suddenly, they have to adapt back to working to supply water. In another day or so they will be back to normal without adding more water.

I know my drainage is good and fast, and I know the media is moist--no need to water.

Millet, I completely agree with your findings, for the last two years I have watered all my citrus everyday during summer months. I have never had a problem with over watering. It does get quite hot here 90-100 through the summer.

I'm getting ready to go to Mexico for a week so I set up a drip system for all 9 trees. I did the same last year for 2 weeks and everyone was happy when I returned.

When I bought my large kumquat tree I only watered it once a week and it started dropping leave so I call the nursery I bought it from and they told me to water daily in the summer so I have done so every since in the summer.

The key is as you stated, good draining medium. When I water my trees within seconds the water is draining out the bottom.

John

John, Amen to all that you wrote. - Millet

Millet, you said that "CHC is the ground up brown hard shell of coconuts", but I think it is actually the chips from the husk, not the interior hard shell. Both CHC and coir have a lot of fiber and that comes from the outer husk of the coconut, not the interior hard shell.

Tolumnia yes, knowing your background, I would think you might be correct. I'll have to look into the answer through The Crystal Company. The largest commercial size CHC chip sold to the nursery industry, that I am aware of is a 1 inch chip. Would not such a large chip have to come from some part of the entire shell? I am not sure of the answer to this question myself. I do know that Crystal Company puts the product through a high pressure press to break up the coconut, creating a lot of cracks throughout the chip, that gives the chip its spongy feeling, and the chips ability to quickly absorb water. In coconut producing countries such a Sri Lanka, the coconut manufacturing companies literally have huge mountains of coconut shells that are left over from the extraction of the coconut oil and the editable meat. Getting rid of the hard outer covering has been a major problem. A lot of it is treated and sold as charcoal. - Millet