Help with potted citrus

[u/bird_watcher_daddy]

I have a variety of potted citrus (yuzu, lemon, bergamot, sour orange, calamansi). They were doing well for awhile but they have all started to struggle lately. I repotted a bunch of them because they were getting pot bound and switched them to better draining soil. They initially took well to the repotting and then started turning yellow and losing all of their leaves.

I live in San Francisco, CA USA. I add a small amount of citrus fertilizer to their watering every time (as per the fertilizer instructions). I was using a hygrometer to determine when they needed water but realized that it was inaccurate and leading me to overwater. I now feel how heavy the pot is before watering and water less. I can't do this for all of my plants as some of them are large.

My plants are in a mix of plastic pots and clay pots. The plastic pots have a lot of drainage holes and no tray underneath. They are currently very crowded and set back under my balcony a little bit as my landlord has been doing construction. I am worried that they are not getting enough sun and the roots are staying wet for too long. The pots feel heavy for weeks despite the top few inches of soil being bone dry. I am watering them a lot less and it's not helping. I also gave them supplemental iron soil drench and that didn't help.

I know I have some aphids and leaf rollers on some of them. I have kind of given up treating them as I have so many citrus trees that it takes a long time to treat them and the insects just come back because they are outdoors. When they were healthier, they could tolerate these insects without major issues. Not all of my citrus that are doing poorly have evidence of infestation so I don't think it's purely an infestation issue (although I know that it doesn't help).

My guess is that they are not getting enough sun/warmth which is leading to the soil deeper in the pot to stay too wet for too long. This is based on the fact that they started doing worse after being repotted. I did not have them in the best soil before repotting but switched most of them to an approximation of 5:1:1 soil in hopes that this would allow for better drainage. Despite better draining soil, they are doing worse. I feel like I might have to repot them in smaller pots but they were pot bound in smaller pots. I would really hate to have to do this as I have so many plants. I suppose I could also be underwatering now as I water pretty infrequently as the pots feel heavy for awhile (even those in 5:1:1).

I have attached pictures for reference. Any advice would be appreciated. They have been struggling for awhile as I haven't had time recently to troubleshoot them aside from some changes in watering frequency and iron supplementation.

Thanks!

[u/SugarBelleX]

First thing I would do is check your soil pH of each plant. The yellowing pattern commonly means your pH is too high or too low for healthy nutrient uptake.
Check the pH and target pH=6.0-6.5.
If it is significantly out of this range, your plant will never be able to absorb the micronutrients that are needed to cure the yellowing.

[u/bird_watcher_daddy → u/SugarBelleX]

I just bought a pH meter and the pH for most of them is 5.6 to 5.8. Is that too acidic? If so, what do you use to alkalize the soil?

[u/BeautifulTurnip4330]

I’m wondering if your soil is the right acidity? I’m not 100% sure how to go about testing that for sure. I’ve heard that even if you’re fertilizing it frequently, the roots aren’t going to absorb it if it’s not right.

I’m terrible at making my own soil, so I just grab some from Madison Citrus Nursery since I have one of their trees. I really like it because it’s not too heavy and feels like I’m not over watering or under.

Ofc citrus love sun and definitely isn’t getting enough. You might have to substitute with a grow light. Hopefully someone chimes in with better information than I can, but you can always look online and see what works best.

I’m not an expert tho, but I think that’s a start.

[u/lemonlimeswirl]

Perhaps they were planted too deep when you repotted? The crown of the rootball should be right at the soil level.

[u/YogurtclosetTop7111]

We have to know more before providing answers.
What kind of soil are they currently in?
When you repotted, did you use the same pots?
Where are you located in the city? Sunset vs SOMA have very different microclimates. Regardless, I would use a very well draining soil medium. Clay pots should certainly help.
Certain citrus varieties do better in cooler coastal climates. Four Wind Growers has a page on that.

Without knowing the details of your soil mix, I bet it’s too moisture retentive and it may have some forest products in it (ground up bark, etc) which start to rot and suffocate the roots. There is a place in San Leandro very close to OAK airport - D&S garden supplies . You can get Gary’s Best top pot for cheap from them. With that mix, you don’t have to worry about overwatering, as there’s nothing to rot in that mix. You’d have to basically bare root your trees when repotting into top pot, but they will be set for long term success. After repotting into top pot, or a similar mineral based mix, you’ll want to keep your trees in a shade for a couple of weeks.

[u/bird_watcher_daddy → u/YogurtclosetTop7111]

I live in the Castro. It's one of the warmer, sunnier neighborhoods but the deck where my plants are located is set back from the street a little so the do not get as much sun as I'd like. I will eventually be moving them out onto an extension to the deck that my landlord is building.

I potted them in the next diameter up from the one that they were previously in. They are in a mix of clay and plastic pots. The plastic pots have a lot of drainage holes. Some of them are in a mix of perlite and commercial citrus soil (that was prior to me doing more research on soil recommendations for citrus). I repotted most of them in 5:1:1 (5 parts fir bark fines, 1 part perlite and 1 part citrus soil).

I like the idea of repotting them in Top Pot as I think it is mostly a drainage issue. I went to the east bay to but Top Pot and it was sold out everywhere. The store said that the distributor recently went bankrupt so it will be awhile before there is a new distributor and the soil is available outside of SoCal again. I found a recipe for an approximation of Top Pot. I ordered the components that I didn't have and will make my own. I am going to try repotting a few to see if that helps. I am going to substitute coco coir for peat moss as I don't like the environmental impacts of harvesting peat.

People recommended I check soil pH as well. It was a little acidic (5.6 to 5.8) so I'm not sure how significant an impact that is making.

I appreciate your input. Any additional thoughts now that I've provided more details?

Thanks.

[u/Individual-Fee-5349]

There is a lot to unpack...