Even a new shipment of rare plants that I potted up today at the Huntington had mold growing on them. This time of the year I am finding mold. Haworthia, from my experience of growing them for the past 30 years, I noticed in hot weather even in Africa they shut down part of the year for about 3 months, they shed the old roots, which will become their fertilizer. I take a plant out of the soil when it does this which is now, law it on it's side on the top of the soil, and wait until I see the new roots growing, then replant it in fresh dry soil, and wait about two weeks before or longer before I start to water again. At that time I take off the dead roots, leaves and while upside down inspect for scale, use Windex, mealies, and wash with soap and water. This works for me, it may not work for you, I also add diatomaceous earth agg. quality that the mealies cannot live in, get it at a nursery. This information is not meant to start a war here, the lady is asking for help. Norma

Hello! I posted here many months ago (about a wilty ficus lyrata) and received some great advise from tapla and litterbuggy. Now that it is a better time to do a full repot, I want to make sure I have everything in order! I plan to use the gritty mix and have gathered all the materials and begun sifting. I am using fir bark (pretty sure fir or pine/fir mix from Rocky Mountain soils, found at Ace), Napa “floor dry” (diatomaceous earth), and manna pro poultry grit. I just started sifting the bark through a homemade 1/4” screener. I sifted a couple batches and noticed the sifted mix seems to have a lot of long, thin sapwood in it. I’ve read sapwood is not ideal to have in the mix. I attached pictures of what my ingredients look like and a close up of the “sapwood” I’m talking about. Is this something I can work with by hand picking out pieces or would it be advisable to find a more pure pine/fir bark mulch? Do my other two ingredients look acceptable? Any other materials you would recommend to a first time re-potter? Do I need a dedicated root saw or can I get away with using an old sterilized kitchen knife? Bark and sifting setup Sapwood I hand picked out Gritty mix: DE - sifted bark - grit

My hope is that many of you will bookmark this post and provide a link whenever you come across posts written by others in search of a remedy for problems caused by a saturated medium. As a member of Garden Web/ Houzz who has been assisting members with their container gardening adventures since 2004, I’ve discovered that an extremely high % of the problems growers bump up against are related to excess water retention in the media (soils) they use. The cause of some of these issues, like poor growth and spoiled foliage, are often very apparent. In other cases, where insect infestation and diseases are at issue, the cause might not be isolated as facilely; still, root systems in poor health and with limited ability to function efficiently due to excess water retention in the medium, affect the plant’s metabolism, which in turn affects the effectiveness of the plant’s natural defenses against diseases and insect herbivory. So, where we might be inclined to levy blame for low vitality levels in plants affected by the insects/ diseases we can readily see, in most cases the opposite is true. Low vitality/ weakened plants that result from poor root health, caused by excess water and an insufficient volume of oxygen in the root zone, is the reason underlying most cases of root/foliage diseases and insect predation. Without question, the best way to resolve problems related to excess water retention is by using a soil that allows you to water correctly. This means using a soil that allows you to water to beyond the point of saturation, so water is draining freely from the drain hole(s) w/o the plant being necessarily punished by a subsequent period of soil saturation that limits root function and damages root health. Understanding what drives water retention in container soils probably represents the largest step forward a container gardener can take at any one point in time. Read more about it here. Perched water is water that is so tightly held by the force of capillarity it won’t leave the pot, even though the force of gravity is exerting its downward pull. Capillarity is the sum of the forces of cohesion and adhesion and what causes sponges to be moist, even after we thoroughly wring them out. Cohesion causes water molecules to stick to other water molecules, which is why water forms drops. Adhesion causes water to stick to dissimilar molecules, like those in soil particles and pot walls, and is the reason that drops of water can be observed adhering to even perfectly vertical surfaces. Acting together, the cohesive and adhesive forces in container media are regularly observed to be stronger than gravity, thus preventing water from moving downward and out of media through the drain hole(s) that should be a part of every conventional container planting. When capillary attraction is stronger than gravity, water ‘perches in the soil above the container’s bottom. Since it is primarily the saturated fraction of the medium that acts to limit root health/ function, anything we can do to reduce the amount of saturated soil in a container, the less potential soil saturation has to limit root health/ function. Finally, to the point of this post, which focuses on how to use ballast to limit the volume of soil in any container that is capable of holding perched water. First, though, it is important to note that the amount of perched water a soil can hold varies from one soil to another and by container size shape; BUT, the height of the perched water table supported by any given soil will be the same in any container size/shape used. That MG Moisture Control Soil you might use, the one that supports 6” of saturation at the bottom of the pot? No matter what the size or shape of the container, when the soil is saturated, it will always support 6” of saturation, i.e. until that ht. is reduced by way of evaporation or evapotranspiration. If we use a “drainage layer” of stones/ gravel/ packing peanuts …, it doesn’t increase drainage. E.g., if we have a pot that is 12” deep and a soil that supports 6” of perched water at the bottom of the pot, adding a “drainage layer” simply causes water to perch to a ht of 6” above the drainage layer. Whereas the max height of the drainage layer would be 6” from the container’s bottom w/o a drainage layer, adding a 3” “drainage layer”would cause water to perch above that to a ht of 9”, which is actually an effort that ends up being self-defeating. Let’s use our mind’s eye for a moment to visualize what using ballast can do for us in terms of reducing retention of unwanted or excess water. We already learned that the potential ht of a perched water table remains constant for any given soil. For this visualization, we will use a soil that supports 4” of perched water/ soggy soil. Let’s also imagine that our container is 9x9x10” deep. The potential volume of soil saturated with perched water is equal to 9x9x4, or 324 cubic inches. But what happens if you place a 4x4x8” brick in the bottom of the pot as ballast before you fill it? The brick takes up 128 cubic inches of space that would otherwise be occupied by saturated soil. Let’s add 2 bricks, so the amount of soil that can hold perched water is reduced from the 324 cubic inches w/o the 2 bricks as ballast, to only 68 cubic inches, with ballast - less than 1/5 the amount before adding ballast. With a little planning, you can reduce the volume to less than 10% of the amount of soil saturated before adding ballast, which goes a very long way toward providing a remedy for woes related to saturated soils. One very important consideration relates to the fact that there must be a continual soil column that extends from the top of the soil to the bottom of the pot. If you had an 8x8x12” pot and were using a soil that supports 4” of perched water, adding 2 – 4x4x8 bricks would fill the bottom of the pot, which would cause water to perch 4” above the bricks; but, if there was a small crack between the bricks that allowed an unbroken soil column from the soil mass above the bricks to the bottom of the pot, the only perched water in the entire configuration would reside in the soil occupying the small space between the bricks. In addition to using ballast, there are other tricks that employ some simple science that allow you to reduce the amount of water a given soil can hold. You can read more about them here. You can read more about them here. The first link I left, at the end of the second paragraph above, explains a concept that makes growing proficiently much easier on multiple fronts. I highly recommend you take the time to become familiar with it to the degree that by default, it's part of the compendium of container gardening knowledge you can apply at will. When you understand and put the concept it explains to work, using ballast won't be necessary. If you think it might be helpful, I can provide a few sketches I drew that should help to clarify some of the info provided. Take care. Al

I haven't been on Houzz lately, otherwise I could have answered your mystery much quicker! Yes, they are oribatid mites (Euzetes globulus) and are beneficials. Here are some high magnification photos that I previously took with a friend's microscope (he is a microbiologist). If you would like to see the difference between living oribatid and spider mites, here is a video I took. It clearly shows the distinctive anatomy of both mites: https://www.youtube.com/watch?v=xrNa9N2olsg Dinie - I suspect you may have gotten them for a certain greenhouse. Oribatid mites are commonly found on cultivated orchids, which is described in this discussion posted by the AOS (American Orchid Society): http://www.aos.org/orchids/orchid-pests-diseases/mites-on-cultivated-orchids.aspx For those who don't like crawly things, these are quite resilient creatures but some miticides will kill them. Personally I find them a bit creepy but they are also fascinating at the same time.