Why are these orange tree leaves yellowing?

It’s been sunny, hot, and dry here. Daytime temps in the 80’s with no rain. I think I’ve been careful not to over water or over fertilize. Have been watering twice per week, and monitoring the soil moisture with a probe. The soil drains well, so chance of over watering is slim. garden soil mixed with sand in the hole with sand being the genearl overall soil. Could I be under watering? The tree was planted a month ago, and showed some new growth so I fertilized lightly once with some blood meal I had, and some 10-10-10, and a little Miracle Gro a couple of weeks ago. Anything to worry about? Suggestions and comments appreciated. Thanks, Ed

This always happens to me with a newly transplanted citrus. I wouldn’t worry at this stage.

You said you’ve had it for a month and so far have added blood meal, 10-10-10 and miracle grow. Don’t know what amount you gave it, but it seems like a lot for such a small tree. Like @gsims1997 said, it probably just needs time to acclimate.

And ditch the general purpose fertilizers. Citrus needs a specific formulation with micro-nutrients which most fertilizers don’t seem to have.

OK, thanks. I didn’t give it much fertilizer. I only gave it a little after it was in the ground and it was showing some new growth. We started it from seed a couple of years ago and it was pretty severely neglected at my in-laws house in a pot for 2 years. In the future, I will be using Miracid on it which has lots of nitrogen, and macros and micros. We are in a level D1 drought, norain in sight, quickly headed for D2. Maybe a bit more water? Is mulching a good idea?

Make sure to water it every other day right after it starts to cool down for the day for about two more weeks. Me I find Silica Blast to work great during transplanting because it helps a lot with the heat stress that newly planted plants have. Poor roots leads to heat stress during transplanting, in ground plants need more impressive roots than they need in a pot that is why water every other day. It looks to me like it’s fine so far. Also adding some gypsum to the soil might help. It’s calcium without changing PH. A shortage on calcium can weaken a plant and make the leaves look like that, then again heat stress can do the same thing. It’s never good to add nitrogen to the soil during transplanting it burns the poorly developed roots at a time that is already stressful for the plants, citrus are more sensitive to a lot of things than a lot of other types of plants, so for a citrus still adjusting to a transplant to the ground it’s looking very good.

Alan thanks. I had a soil test done, and because of the oaks in the area which shed their leaves year round, the ph of the surrounding natural sand/lawn area is 4.7. I’m familiar with the calcium methods. I used to add gypsum to my blueberry mix for just that reason, to add calcium and keep the ph low. I could probably add a little gypsum to the planting hole area for the calcium, but I’ve limed the whole lawn to try and get the ph up. Also had a few oak trees removed. I didn’t use too much fertilizer on the tree, and only after it was pushing new growth. I think I will water every couple of days. Is mulching suggested? I haven’t yet.

The more hot and dry it is the more that mulch can help. Poor roots equals easier for plant to get drier.

Will add a little mulch tomorrow, probably helps moderate soil temp too.

Yes moisture can absorb lots of heat before it can get in to the ground if it’s in mulch.

Yes mulching will certainly help especially in drought conditions as it will cool the ground beneath it and help retain moisture. I usually use about 2-3" out past the drip line. Keep the mulch away from the trunk to avoid collar rot. Enjoy your citrus… mine in the Southern Hemisphere are just starting to ripen.

Mick

Thanks. I was also considering temporarily lowering the pH of the water I’m using, since that’s all the tree is drinking until the rains start. The pH of the soil in the planting hole is probably around 7, and the pH of our tap water is 8. Adding 3 tablespoons of white vinegar per watering can brings the pH of the water to 6. This might help a lot.

Another theory. These are old leaves the plant is sloughing off to concentrate on all the new growth that looks very good. This little tree hasn’t had any TLC for a couple of years, and is probably going to the next level.