I have horsetail plants in planter boxes outside my southern windows in Seattle. They did great for a while, but over the last year, they haven't looked so good. As you can see in the first photo, most of them have gotten pretty yellow. Last Spring/Summer, I barely got any new growth. This Spring, I was excited to see lots of new stalks coming up. But as you can see in the second photo, the new stalks have started to turn white and die :( They are in regular potting soil which I keep moist. I can't find anything online to help me diagnose the problem because every source just talks about how resilient they are, how they grow like a weed in pretty much any soil, in varying light conditions and moisture levels. The only difficulty I've read about people having with Horsetail is how to contain it. I'm not a plant novice and I have lots of healthy indoor and outdoor plants. I'm perplexed by this typically super hardy plant. Any insight would be much appreciated.

I've often left these 2 explanations on this forum about questions that come up about the 2 following features of Ficus leaf anatomy. Ficus Anatomy Foliar glands in the inferior leaf surface at the leaf to petiole (leaf stem) transition are a normal part of Ficus anatomy, and so far, their purpose is not fully understood. They used to be referred to as 'wax' glands, and occur in a high % of the plants in the Moraceae family, including mulberry. Newer literature refers to the gland as a phenolic gland, because of the heavy deposits of phenolic compounds in the glandular region. Any exudates (oozings) that originate in the near vicinity of the gland are probably latex or residuals from same and not related to the gland itself. Ficus leaves often have other semi-regularly spaced white dots, which vary in salience, inside and roughly parallel to leaf margins and often misidentified as pests or glands. They are lithocysts, enlarged cells that contain crystals of calcium carbonate or calcium oxylate called cystoliths, and are another normal part of Ficus anatomy. Al

Copied from another users reply; ”#1--most Calathea are not high light plants. This is a good rule of thumb to follow for light: if a plant has leaves that have red or maroon undersides, its a shade or low light plant. The red coloration is a genetic adaptation of rainforest plants that thrive in moderate to deep shade. The pigment is made up of specialized cells adapted to catching what is called "green light"...this is light that filters through the canopy layer, hits the ground and bounces back up. These plants with red undersides are specifically adapted to catching and utilizing green light. So putting your plant right in an unobstructed South facing window might have been a little too much light all at once.” So, being a low light calathea, the undersides will start to lose the purple tone with more light. You could put it in a more shaded spot which may darken then again but it’s not doing the plant any harm being green. Chloé

Oh my goodness thank you so so much for the detailed answer! that is incredibly helpful! I remember the desire to do well by my plants when I first started practicing bonsai, long before the answer to every question could be found online, so I also remember all my concerns detracting from the whole growing experience. I enjoy trying to help others get more from their growing experience, and that serves nicely as a natural extension of my own growing experience, so I'm glad you found it helpful. the soil does stay moist for a long time (i’ve had it for a month or two and have only gotten to water it twice- the second time being when i changed pots, so the soil was dry), where i live is extremely humid so that could definitely contribute! I became interested in soil science since about 1980, and I've been tinkering with soil sense. This thread, about container soils, is chock-full of information. Understanding the concept that drives water retention in container media is probably the largest step forward a container gardener can make. A grow medium with so much water retention that watering intervals are measured in weeks is a problem for almost any plant one would be likely to grow in a container. I make all my soils and I try to make them so watering intervals once the roots have colonized the soil mass are no more than 3-5 days. Excess water is always a problem for terrestrial plants, and when it's present the question isn't whether of not the planting has lost potential (in terms of growth rate, yields when applicable, vitality (health), and the plant's ability to defend itself against insect predation and disease vectors/pathogens. did untagle the roots (it was practically a solid mat of roots!), and i did mix the old medium with well draining soil and added perlite when repotting. Just what type of soil did you mix with the old soil, and at what approximate proportion? That might be a factor re the Ca deficiency I mentioned if you didn't include and dolomite (garden lime) in the new mix. but you’re definitely right, the soil drying out has been a big problem i’ve noticed. do you have any advice on how i can better drain the soil? I know for certain I can help you in that regard, but first let's see what you did insofar as the new soil is concerned. i’m kinda at a loss on how to do that :( and yes i would love to know about fertilizing! i haven’t yet fertilized it, could that possibly be a problem? Maybe yes, maybe no. Usually new plants (how long have you had yours?) have an adequate amount of residual fertilizer in the grow medium to carry them through several waterings; but that said, NOT having a nutritional supplementation program in place is always a problem. Depending on nutrients that become available through breakdown of the grow medium is very seldom an appropriate strategy. There are many plants that grow slowly and require little in the way of nutrition, but philodendron is definitely not one of them. Some succulents or cacti and the carnivorous plants fit into categories of plants that might not require fertilizing often or at all. If you're watering correctly, you should probably be fertilizing at every 3rd to 4th watering in summer and at every 5th to 6th watering in winter. Don't let yourself be told you should be abandoning fertilizing during the winter months. Does Mother Nature travel the world pulling nutrients from the soil when leaves start falling, and put them back in spring? I probably committed some sort of logical fallacy in that last, but the point remains - plants need a full compliment of ALL nutrients essential to normal growth, in the soil and available for uptake at all times. Even during the consequential dormant phase, roots continue to grow until soil temps drop below 40-44*F. i’m nervous to because i worry that i would over-fertilize it. I can help you avoid that, so not to worry. and i do have one more question if that’s alright! do you think the soil staying too moist could have led to bacteria or fungal growth as well? that’s what i’ve heard from people who have issues that look similar to mine. they all seem to say to cut the infected leaves off and apply a fungicide, but all of my leaves are “infected.” Low oxygen levels, an obligate partner of too much water in the soil, often sets the stage for fungal infections of roots and lower stems by any of the several fungi gathered under the umbrella term of 'damping-off diseases', but I don't think that's where you are. Your plant's symptoms are consistent with a bit of mechanical injury (like bruising) caused by wind or less than careful handling before you acquired the plant, and with over-watering/ soil staying wet too long. I think that should be your primary focus at this point. would it be good to cut just the brown and yellow parts away to stop it from spreading or is that a bad idea? or maybe just not even the issue? sorry for all the questions ..... i haven’t had much luck getting clear answers, so this helps so much!! There is nothing in the images to suggest that removing any of the leaves shown would be a net benefit to the plant, in fact, it would not be in the plant's best interest to remove the spoiled foliage. That doesn't mean you will injure the plant or put its viability at risk, It just means it would be better to let the plant decide. The plant has internal chemical messengers that keep plant central apprised of whether or not each individual leaf is pulling its weight. As a leaf is reaching the point where it's using more energy than it can create during photosynthesis, the flow of a growth regulator (auxin) triggers a series of responses that end in the shedding of the leaf. The first response, resorption, is inconspicuous. During resorption, the plant will 'extract' whatever can be used elsewhere in the plant. Some of the nutrients which are capable of being moved from place to place within the plant (nitrogen, phosphorous, potassium, magnesium) are salvaged along with other bio-compounds. As this process reaches its end stage, the slowed flow of the chemical I mentioned causes a wall (abscission layer) to form at the base of the leaf where it attaches to the branch. The 'wall' isolates the leaf from the plant such that nothing further can move across the abscission zone or through the abscission layer. Soon after the layer is complete, the weight of the leaf (in most cases) causes it to separate from the plant Leaves are little food factories where the plant's true food (sugar/glucose) is synthesized. So, removing a leaf denies the plant the food the leaf is making, and it denies the plant the ability to take back some of what it already paid for during the resorption process. That doesn't mean you should or shouldn't remove leaves you find offensive. That's for you to decide, but at least you now have information enough to make an informed decision. Removing leaves from a healthy plant is seldom a life threatening issue, especially if the timing favors the plant, but when plants are circling the drain, its in the plant's best interest that the grower is very judicious about removing any of its remaining food sources (leaves). What questions are you left with? This is Foliage-Pro 9-3-6 fertilizer, and what I recommend you use as your 'go to' fertilizer for almost anything you're likely to grow in a container. The reasons I recommend it are many, and there are precious few fertilizers out there which are even in the same league with it. You might enjoy: June, freshly pruned ^^^ 8 weeks later ^^^ pruned again and branches wired ^^^ ficus benjamina ^^^ After defoliation ^^^ wired and pushing a new flush of foliage ^^^ Al