Good soil health important for healthy trees

Q: I bought the iron chelate stuff you recommended, however the instructions were not really clear.  This was for the lemon tree in the whiskey barrel with yellowing and not too many leaves. Anyway, I put about 3 teaspoons in the barrel and applied water.  I did not know this was going to turn the water red.  It all drained out red.  Hopefully enough stayed in to help the tree.  When should I do this again?

A: Well, the water coming out all red is not a good indicator of good soil health. It also means that any fertilizer applied is going to run through it as well. I would go to foliar fertilizer applications until you can improve the soil.

This EDDHA iron chelate that I recommend is not a good iron fertilizer for a liquid application to the leaves. Sorry. But it will be great once you improve the soil and it holds nutrients again, and you apply it at the right time.

Another method you could use would be to lift out the whole root ball out of the container if it will come out easily for you and in one piece. You can cut around the tree with a shovel and see if you can lift it out of the container. If the root ball wants to fall apart and not come out in one piece, then I would forget lifting it out and replace the soil a bit each year.

If the tree can be lifted out, dump the excess soil left in the container, wash some of the soil from the roots and replant it after sanitizing the container.

You can inspect the roots and cut off any unhealthy ones when it is out of the container. Do not let the roots dry out when you are doing this. Before you replant it, put the tree root ball in a container full of cool but not cold water and let it soak for a couple of hours.

Replant the tree. Stake it for a couple of months and repot the whole thing. Then apply the iron fertilizer you bought to that soil. But you will get very limited results from that iron without improving the soil. If this doesn’t make sense, email me with questions so I know what you understand and don’t understand.

Q: We have a nectarine tree trunk that we have a question about. I am attaching photos of it. It looks like it’s rotting. We were going to wrap the trunk to further protect it but we don’t know if it’s the right thing to do. Please view the photos when you have the time and advise us on what we should do.

A: Nice pictures. I will post them on my blog. It looks like there is damage to the trunk as you suggest. I would pull the rock away from the trunk about a foot. Make sure that the source of the irrigation is not close to the trunk. Put the water source a foot to 18 inches from it if possible. Second , make sure you are not watering too often. You should be watering right now about every seven to 10 days but with a large volume of water when you do enough to wet the soil to a depth of 18 to 24 inches on at least two sides of the tree. Three or four emitters watering this tree would be better than just two as the tree gets bigger.

Pull the bark away from the damaged area if the bark pulls away easily. If it doesn’t, then cut the bark away with a sanitized knife so the damaged area is exposed and clean for healing. Keep water off of the damaged area during irrigations until it heals, perhaps around May or June.

If the rock was put around the trunk and it keeps the trunk wet above the soil line for the first several years, you may very well encourage trunk rot or collar rot on young trees. On young trees it is important to keep mulch away from the trunk a foot or so for five years or more until the trunk matures and is less susceptible to rotting. Second , never irrigate frequently but deeply and less often.

Q: My grapefruit tree is about 25 years old and has always produced an abundance of fruit.  A few months ago, I noticed a crystallized substance coming out of various spots on its lower trunk.  Also, some of the leaves had developed tiny black spots, had turned yellow and had fallen from the branches. I attached photos.

I would appreciate any help you can give me about this and what to do to stop the flow and save the tree. There are about a dozen or so grapefruit on the tree now. Are they OK to eat?

A: I posted your photos on my blog for others to see. Probably my biggest concern for your tree is it getting enough water and applied at the right times and deep enough. Frequently, this type of damage is associated more with stress than anything else.

It is also possible that this could be the result of some cold/freezing damage from a previous cold winter. In other words, I do not believe it is because of insects or an active disease. It is possible it is because of some "disease" caused from environmental stress. This type of damage can revert to an active disease problem if you do not keep the tree healthy.

So my recommendation is to not put down any chemicals for insects or disease but to concentrate on plant health by fertilizing in the spring with a citrus fertilizer. This would be done around or before flowering.

Put the fertilizer near the drip emitters or source of water so the fertilizer is pushed into the root zone of the plant. You might want to take a look at tree fertilizer stakes but keep them at least a couple of feet from the trunk. If the source of water for irrigation is close to the trunk, move it away the same distance. 

It is OK to start with two drip emitters for  new trees but in a few years you should be adding more emitters that will allow you to spread the water more evenly under the trunk and add more water as it gets bigger. Bigger trees need more water than smaller trees regardless of the type of tree .

This spring water the area under the canopy deeply and thoroughly. Add an iron chelate fertilizer when you are adding your other fertilizer as either granular, liquid or tree stakes. Like any fertilizer, it needs water to move these fertilizer salts into the root zone.

Prune out any dead or dying branches, crossed branches, branches growing straight up or straight down. These are unproductive and just shade the interior of the tree.

The fruit is fine to eat as long as you have not applied any pesticides recently.

Bob Morris is a horticulture expert living in Las Vegas; he is on special assignment in Balkh Province, Afghanistan, for the University of California, Davis. Visit his blog at xtremehorticulture.blospot.com

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