Pots are on the large size for so small of plants. This can and easily does lead to over-watering, the entire medium in the pot acting as reservoir for water. Then too, if mites are present, that could further affect matters. But I'd look at all cultural (environmental) aspects before blaming an organism.

The potting mix is as follows:

5 parts Scotsman's Choice Landscape Mix for fine bark

1 part perlite

1 part peat moss

1 tablespoon of lime per gallon of mix

I wonder if my mix didn't need the lime and made the mix too alkaline? I don't have a pH tester, but if you know a good one off Amazon, let me know. I found several sources that seemed to suggest a 5-1-1 mix like my own would do better with lime.

wisconsitom, I jumped the gun with larger pots way too early. However, I have spaced my waterings out to compensate.

Looking at the color of the Taxodium versus the green Metasequoia, it looks like the you didn't need as much lime. That's also an inherently nutrient poor mix and you haven't mentioned anything about fertilizer.

I should have posted pictures of all the tree seedlings to give a full picture.

What should I do to correct the pH?

For fertilizer, I use Dyna-Gro Foliage Pro and pro-tekt.

If you guys have suggestions for a good pH tester I can order from Amazon, please let me know.

Assuming that my potting mix pH is too high, how can I lower it? I know they make products to lower hydroponic pH, but what about in potting mix?

It's pH BTW. Sorry, all the cheapo testers I'm aware of are not so good. Maybe just start out with litmus test paper to see if you're in the ballpark.

I corrected pH in all my posts. Anyway, I guess I'll get some test strips. I wish I could say I was doing a better job on my first try growing trees from seed.

If this is your first attempt, don't be so hard on yourself. You'll get there. And believe me, you're far, far, far from the only one who doesn't or didn't know how to write pH. I see every variant every day! Take care, and let us know how tings go going forward.

I appreciate the advice. I ordered some test strips and I also have a solution for the mites on the way. At this point I'm leaning towards alkaline potting mix being the main problem and the mites coming in after the seedlings were weak.

The webbing looks like normal spider webs, not spider mites, so that has nothing to do with your problem.

Give those seedlings some time to get more roots to absorb the nutrients in your media.

Mike, thanks for the input. It isn't in these pictures, but I removed webbing on the underside of nearly all the trees and killed some of the mites by hand. I used a light dose of cykick too. There are regular spiders too. I agree that I don't think mites are the main problem, but I find it hard to believe that there isn't something else wrong.

Bottom left are reference points (I wanted to make sure the strips were working right). The dark is Pro-Tekt and the red is Foliage Pro. To the right of the dark 11-14 is RO water. To the right of that is softened water.

The top right consists of irrigation water and potting mix soaked with RO water. It doesn't appear like anything is out of the norm here. Is it possible for the alkalinity of the water to still be off even though the pH of the water is neutral? The irrigation water is well water pumped into a reservoir.

Edit: I'm doing a larger test on the potting mix now that involves using more mix with equal amounts of water. I'll post if anything unusual comes up.

Left is RO water and right is RO water soaked with potting mix for 2 minutes. Once again, nothing crazy here.

TL;DR: pH testing indicates potting mix and irrigation water is neutral to slightly alkaline.

Taylor, indeed you ask an excellent question: So, while we tend to occupy ourselves with worrying about soil pH, the pH of water used has almost no bearing on this. What does matter is water alkalinity, and no, that is not the same thing as water pH. so one could be supplying excess cations (calcium, magnesium, some others) even though pH is not out of whack. Such is the case where I happen to live. Our tap water is not excessively high pH but it is quite alkaline. For some of the specialty plants I work with in the ornamental phase of my deal here, I sue specialized fertilizers to drive down this alkalinity. Such items exist. Look at brands like Peters, Plant Marvel, and possibly some others.

Wisconsitom, what are your thoughts about adding some vinegar to my irrigation water prior to watering my tree seedlings? From what I've read, it is the most user friendly way to lower water alkalinity. I could test the pH of the water before applying it to the seedling to ensure it isn't too acidic and see if I get some results.

The other thought is maybe I am watering too much like you mentioned earlier, but it doesn't make sense because my seedlings in smaller trays are not growing any faster than the ones in larger containers.

Vinegar is indeed a relatively safe addition for water acidification..........so long as you do check! Even acid-loving plants have their limits, at which whole groups of nutrients become unavailable. So do check closely.

I can't account for the seeming similarity of the ones shown here and those you mention in trays. I'm not saying I disbelieve you. It's just that I'm not actually there, checking things out. Good luck!

I still haven't ruled out that it is the larger pots hampering them. The ones in my seed tray do appear healthier, but they are no larger than the ones in my containers nor do they appear to be growing any faster.

Let's see what adding vinegar does and maybe trying to space out my watering even more on my larger containers. I have to be careful though. I lost a metasequoia in one of my seed trays from being late with water last week.

You want moist, not soaking wet. Whatever regimen gets you there is the one to use.

I have had very little progress on this issue. I have concluded that the pH and alkalinity of the water is not the main problem. I have gone back to the potting mix as the issue. Specifically, I believe that I didn't properly screen out fine particles in the bark portion of my 5-1-1 mix which has lead to poor drainage. The reason why some of my trees are doing so much better than others is pure luck. Those pots happen to have a potting mix that had fewer fine bark particles than others.

This is only a hypothesis, but it's all I can think of. I have sifting screens now and will soon test this out on some of my taxodium seedlings in smaller trays when I move them to 1 gallon pots.

I transplanted 6 taxodium mucronatums into new 1 gallon containers with a more proper 5-1-1 mix and will see how they do.

Hi Taylor,

I have grown probably over a hundred montezuma cypress trees from seed and have mostly used variations of 5-1-1 mix but also just regular potting soil from Lowes and in general they are pretty forgiving trees. When did you start your trees this year? Seeing that you are in zone 9, it is pretty hot and the one thing that really affects trees this time of year in pots is the heat, especially when young. I find that you start them too late, they don't handle the heat as well. My trees I started this year a much bigger than the ones you showed above.

Here are two 406 or 407 seedlings (I can't remember which tree I got the seed from) that I started earlier this year.

ltruett, thanks for the response. I started the trees from seed in March of this year. I knew something was wrong back in May-June, but I haven't come to any solid conclusions. It is frustrating to see everyone making so much progress while my seedlings are stunted! The 6 montezuma cypress trees that I transplanted yesterday into the new medium where I filtered the dust particles out seems to have much better drainage than my other pots. I am hoping this is the problem and it does seem to be an issue given the fact that nearly 50% of the Lowes potting mix was dust sized particles, but if you have any other suggestions I am more than willing to listen.

I started my trees in morning sun March through June. They now get afternoon sun on the south side of my porch and I regularly water them. It is odd that some of my trees are doing better than others.

I can't say I see anything huge I would change. I generally put the seed out in my trays in January and let nature take its course. If you have a place in the ground to plant them, I would do that sooner than later as they will grow much faster than in pots (as long as you can water and protect them).

This is a MC I grew from seed that I planted at a local elementary school (with 20+ other MC trees) back in 2011 as 1g tree. It doesn't get any irrigation and was stunted the first few years from kids breaking branches and the leader repeatedly before it was finally able to get taller than the kids.

I love the way it looks. I'm a huge fan of MC and BC trees which is why hybrids interest me so much. The area I have set aside for a grove can fit over 20 trees. I haven't decided everything I'm going to plant, but taxodium will comprise the majority of them. Keep me in mind if you have some cones or if there is a way to send me seedlings later on. I think I have my profile set to where you can privately message me on here (if not let me know). I can give you shipping instructions for cones.

It looks like 2 of the 6 transplants won't make it going into the new 1 gal pots. I was a little rough on them. The other 4 are looking ok and I could be imagining it, but a couple of them look like they may be putting on growth.