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Underfed mandarin?

Posted by nika107 Zone 24 (My Page) on
Mon, Apr 7, 14 at 13:13

First of all, I really want to thank all of you who have been helping me in this citrus journey of mine over the course of the last 12 months. I'm learning so much every day and I appreciate everyone who has offered suggestions!!!

This tango mandarin is still struggling. Like many others here in North San Diego, my soil is very heavy clay and slow draining. We amended the soil at planting time, but I don't think we did enough. I just fed it with EB Stone Citrus food about 3 weeks ago. Because the tree has been in the ground for one year, I followed the feeding directions for a one-year old tree and scattered one cup of the fertilizer around the drip line. So now the soil is still rather slow draining (we haven't watered in over a week, and yet the moisture meter is still reading in the green about 6-7" down). Plus I just tested the pH and it's pegged on 8 on my meter. So based on what I'm learning, here are what I think are my choices:

1. Add GrowMore chelated minerals at the next watering. Then do nothing until the next feeding time in May-June.

2. Assume I didn't feed it enough, since I've come to learn this is more likely a 4 year old tree instead of a one year old tree. Work some lime into the soil to amend the pH and add another cup of EB stone fertilizer now.

3. Work lime into the soil to amend the pH, and instead of the EB Stone, add GrowMore chelated minerals and water with liquid kelp every couple weeks until the next feeding in May-June.

4. Dig up the tree completely and add more soil amendment to the entire area, then replant the tree, and get back on the proper feeding schedule in May.

The tree did get a flush of new leaves and blooms a couple months ago, but the young fruit hasn't progressed passed beebee size and is all turning yellow, so the fruit doesn't seem to be setting. I do have about 5 or 6 fruits that reached almost normal size, and they now have the faintest blush of orange. I also have a handful of new blossoms.

Full tree photo IMG_2483_zps8b9629ff.jpg

Possible water sprout? photo IMG_2482_zpsb5a83c40.jpg


Follow-Up Postings:

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RE: Underfed mandarin?

More food definitely and chelated iron; at pH 8 citrus cannot absorb iron from the soil; so you have to add it in chelated form. Check you EB Stone, which may already have chelated iron... If that is the case, you may only have to add more. Citrus generally do best in soils with pH below 7; so you may do well to add some soil sulfur to lower the pH. Lots of people also add vinegar to their water to lower the pH; but that takes a long time to affect the pH of the soil. I think your plan will help and you will soon have a tree that looks and performs better.


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RE: Underfed mandarin?

I would not recommend trying to improve the soil at this point in time. Some citrus trees have a way of just sitting there for a year or so before they feel comfortable with their environment and start to grow in earnest.

I would be patient with that tree and try not to overwater it. Give it a little N and it might surprise you.


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RE: Underfed mandarin?

The more I look at this tango tree picture the more I am suspecting lack of sun. Is this tree in full sun? Citrus trees need full sun to be healthy and productive.


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RE: Underfed mandarin?

With all due respect, johncha, you are just wrong. First, I didn't recommend improving the soil, only lowering the pH; and soil sulfur is the correct method to do that. In the meanwhile, chelated iron is essential in soils with pH of 8; ask any commercial citrus grower in AZ or the Rio Grande Valley of Texas. As for full sun, of course the tree will grow faster and produce more; but it will do quite well with as little as 2-3 hours of direct sun. Anyway, Nika, it is your tree; do what you want; but you did ask for advice.


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RE: Underfed mandarin?

We have tons of iron in our soils here in S Calif. And, we don't really have pH issues here, with one exception: during the winter, when our temps drop, which can, in the short term, cause issues with both macro and micronutrient absorption. Do not amend the hole, but top dress your trees. If you're on clay, you should be planting your citrus on mounds or in rows in berms, like the commercial growers used to do in areas with large amounts of clay. I

n looking at your tree, my guess is more a combination of too much water causing increased proliferation of Phytophthora (which grow rapidly during our cooler temps in winter and early spring) and some nutrient lock out. Treat with Agrifos now (2 Tbsps. in 5 gals of water, treat 3 times, about 4 weeks apart, then every 6 to 12 months, depending on how your trees look). Watch your soil moisture. Check down 18 to 24" and see if your soil is still wet. If so, don't water so much. You can apply cheleated micronutrients, but to me, and based on what I've experienced here in N. San Diego county, it appears you've got too wet roots and too much Phytophthora, which is our bane here in San Diego county, for both commercial avocado and citrus growers, and of course, us hobbyists. Jon, citrus do like lots of sun, but will actually do well with partial sun as well.

Patty S.


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RE: Underfed mandarin?

I was just speaking in regards to digging it up and improving the soil with amendments and replanting the tree in the same hole. It is a good way to kill a stressed tree. I know this from experience.

As to the sun exposure issue, citrus will grow as an understory tree but will not be vigorous or productive.


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RE: Underfed mandarin?

Jon, you are correct - it is not recommended to amend a hole for a tree. The current recommendation is to plant your tree in the native soil. If you're on clay, the best method is to plant your tree in a raised fashion (berm or mound), to improve drainage. If you wish to amend, top dress with amendments. Clay is actually very rich in micronutrients. If you can address the drainage and moisture issues, citrus do very well in clay. I agree, I don't think digging this tree up is the solution, and with as stressed as it appears to be, it could surely be its demise.

And don't think it has been determined that this tree is growing as an understory tree? I have citrus in my yard that grow in the shade from about noon on, and they are lovely, and full of fruit. The only exception I would say would be grapefruit here, and yet, I have two Rio Reds who are growing in significant shade. One IS an understory tree, under the shade of a very large Pepper tree, and the other is getting crowed out by an enormous Phormium that has just gotten huge in the last 2 years. Both are giving us really great fruit, just need to be on the tree about a month longer to sweeten up. Both are doing well, growing nicely and producing lots of fruit. Which actually, I find rather surprising, as both of these get almost no or no direct sunlight.

And John, we don't need to adjust our pH here. We just need our trees to mature a little, and they do quite well. Their first year or two, if young and too wet, will look like what you're seeing. As long as you can manage your water well, you will not have so much chlorosis, which is actually more due to issues with Manganese, first, which is a little low in our soils here, not so much iron, which we have ample amounts of in our soils here in San Diego county. Our soil conditions are very different than AZ and extremely different than TX. Our commercial citrus growers (those that are left here), do not amend for pH.

Patty S.


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RE: Underfed mandarin?

Well, I was just talking to my husband about it and about two months ago he was watering the tree and forgot about it, and left the hose on for an hour. And this was right when the new growth was flushing (if that's a term). Granted when we water we leave the hose on low and just let the water seep into the ground, but that might explain a few things. Regarding the sunlight, it's getting about 7 hours of afternoon sun, so I think that's ok -- but I very much appreciate every one of you chiming in with your thoughts -- I have lots of good info to chew on this spring!

So I'll start with the agrifos. But should I wait until the soil dries out and then add, or just add now? I'll also check the soil a little deeper from now on. After the application of the agrifos, maybe at the next watering, I'll add some GrowMore. And I need to amend the pH with the soil sulfur. I know citrus have some leeway, but I'm pretty sure the soil is way too alkaline.

I'm going to leave the tree where it is for now. I will certainly add to this thread, for the benefit of any future newbies facing the same issues!

And sincere thanks to you all! :)


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RE: Underfed mandarin?

I would give it a few more days to dry out, and then apply the Agrifos. You can apply a foliar application of GroMore, won't hurt (I never found it helped much for me). Soil sulfur will take several months to work, so be sure not to over-apply. Frankly, you don't need it, but if it makes you feel better :-) Your issue is wet feet.

Patty S.


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RE: Underfed mandarin?

Patty,

I know you don't have to fix your soil; but you don't have pH 8; at pH 8 it doesn't matter how much iron you have in your soil, it is not available to citrus. The easiest answer is soil sulfur; the short term answer is chelated iron.


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RE: Underfed mandarin?

My soil pH can be that high, John. From 7.2 to 8.0 depending on where I test. Nika and I are in very close proximity to each other. I am fortunate I have no clay on my lot, but folks do around me. I understand about micro lock out, in relation to pH but truly, NONE of the commercial growers here in San Diego county that I am aware of ever adjusted their pH for their soils. We just really do not need to do that on any kind of a regular basis. My young citrus will often look like the above photo. It is partially due to micro lockout from two factors - slightly higher pH and cold temps - but it is resolved as our temps warm up and as trees mature. This affectation is magnified with too much water, and the proliferation of Phytophthora, which we DO have a serious issue with here in SD county. All commercial avo and citrus growers DO prophylactically treat for this organism. If you want to use soil sulfur, it won't hurt (as long as you don't put down too much, and if you're very patient), but the tree will most likely recover as our temps warm up, and also as it matures. I am more suspicious of wet roots and Phytophthora, so no amount of soil sulfur will fix that issue. Agrifos works extremely well, that, and controlling the moisture at the root level.

Patty S.


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RE: Underfed mandarin?

I just checked the moisture to see if it's a good time to apply the Agrifos. I haven't watered the tree in probably two weeks. I put the moisture meter at the dripline, pushed it down about 8-10", and the meter is reading all the way up on the border between green and blue on my meter (meaning it's very wet down there). All of the beebee sized fruits the tree put out this spring are yellowing and falling off.

I'm still not going to dig it up, but if it doesn't dry up in another week or so, should I start thinking about it?


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RE: Underfed mandarin?

Yes, nika. Your issues are clearly due to the roots drowning. Not uncommon in overwatered plants in clay that are not planted on a mound or berm. Citrus will actually do well in clay, but the drainage issue must be resolved. Planting in elevated mounds and carefully monitoring your soil moisture will be the key :-) I would not worry about other issues except for Phytophthora, which will be resolved if your moisture issues are fixed. Your pH and micronutrient uptake is most likely not causing this overall failure. Your tree's roots are simply suffocating.

Patty S.


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