The best mix for a hoya is actually soil free. Pick up a bag of fine grade orchid mix (Lowes sells a good orchid mix made by Gubler, get the one in the blue bag). Hoyas are NOT cacti and succulents, and they should not be treated as such. There are some hoyas (austalis ssp. oramicola/rupicola) that would rather be watered once a month, and some hoyas that are very thirsty (buotii, lasiantha, praetorii, javanica/multiflora) and do best grown semi-hydro. The average hoya (carnosa, pubicalyx, most pottsiis, obovata, etc.); however, does best being watered once every 7-10 days. Hoyas are tropical/subtropical plants, and as a rule, they thrive on heat and humidity. There are also exceptions to this rule. Hoyas are epiphytes. In nature, most hoyas grow up trees, using their aerial roots to attach to the trunks. Because hoyas are epiphytic in nature, soil should be avoided or used minimally. Hoyas need a well-draining, airy mix that will provide their roots with enough moisture and areation to prevent rot. The issue with using soil, even when it is mixed in with perlite, is that it compacts. Every time you water, the smaller soil particles sink to the bottom of the pot, compacting together. This leads to blocked drain holes and can cause root rot. The key to a successful, well-draining potting media is to make sure each of your ingredients is the same size. This is another reason I am fond of my mix (1/4 inch orchiata bark, 1/4 inch new zealand sphagum moss or 1/4 inch hydroton balls, and 1/4 inch perlite, one part each...so, if I make 3 cups of mix, it is one cup each ingredient). My mix is expensive, and, unless you have over 300 hoyas, you don't need it (heck, even I don't need it, but it works for me, so I stick with it). I suggested an orchid mix as a substitute, and hoyas do very well in orchid mix. The average hoya should be fed 1/4 strength fertilizer at every watering. I use MiracleGro water soluble tomato food (1/4-1/2 TEAspoon per gallon of water) because it is inexpensive and provides all the micro and macronutrients. The reason you feed at every watering is because in nature, hoyas are fed naturally, in very small amounts. The mists from the jungles run down the trees, and onto the aerial roots of the hoya. Inside this mist water, macro and micronutrients from vegetative decomposition and animal excriment, nourish the hoya in small amounts. Flush your plant once a month to rid the pot of any excess fertilizer residue. You do this by watering the plant for 2-3 minutes straight or soaking the entire pot, plant and all for 2-3 minutes. Hoyas also, for the most part, prefer being rootbound. This means if you repot, don't use a pot bigger than 2 inches larger than the rootball. They like it snug. When you get ready to repot your hoya: *Soak your orchid mix overnight. This flushes out any ecessive tannis that may be present in the bark. It also rids the mix of dust. *The next day, drain and rinse your mix thoroughly. *Remove your plant from the pot. Gently rinse as much of the old potting mix/soil off of the rootball. At this time, check the roots. They should be firm and lack any foul odor. Also, check the stem where the roots attach from. A wee bit of yellow coloration is okay, as long as the stem is firm and has no foul odor. If the stem is soggy, peeling, black, or has a foul odor, you may need to restart your plant entirely by taking cuttings. *Set your plant aside. * If you are using a new pot, soak it in a 1:10 part bleach water solution (1 part bleach to 10 parts water) for 10 minutes or so. Rinse thoroughly. If you are reusing your old pot, rinse all the soil off first, and then soak in bleach water solution for 10 minutes or so and rinse. *Add 1 inch of your orchid mix to the bottom of your pot. Place the rootball of your plant in the pot. Add a bit of mix at a time, gently shaking the plant and pot to get the mix thoroughly around the rootball. Once the rootball is thorougly covered in the mix, top off around the base of the plant, if needed. *Wait a week and water.

Some nutrients are mobile in the plant (nitrogen, phosphorous, potassium, magnesium). The light older leaves is almost certainly indication the plant is robbing (at a minimum) nitrogen and magnesium from older leaves for use in newly emerging foliage. Magnesium is central to molecules of the green pigment, chlorophyll, while nitrogen is essential to formation of amino acids and an important structural component of chlorophyll. There are two theories regarding how plants take up and use nutrients. One is called the 'original theory' and suggests all plants need different NPK %s. The problem with that theory is, no one can decide on or agree what %s of nutrient each plant wants/ needs. That, and the thought that plants WILL take up more of some nutrients than they can use, casts doubt on that theory. Witness the hundreds of different NPK %s and ratios suggested as "critical" to growing healthy AVs as proof of the disagreement re what plants need/ want. In the 1980s, the work of Professor Tom Ericsson, researcher in plant nutrients at the Swedish Agricultural College in Ultuna showed specialty fertilizer products (tomato fertilizer, citrus tree fertilizer, "bloom boosters", orchid fertilizer, ad infinitum) aren’t necessary; that all plants use roughly 6X as much N as P and about 3/5 as much K as N. This is called the 'contrary theory' and has gained wide acceptance since it was discovered. Once the calculations are made, 3:1:2 ratio fertilizers (24-8-16, 12-4-8, and 9-3-6 are all 3:1:2 ratio fertilizers) provide nutrients at almost exactly those rates. The phrase "up - down - all around" came into being as a way to remind us that nitrogen is for the upper part of the plant /shoots and leaves, phosphorous is for the lower part of the plant/ roots, and potassium is for the plant's general well-being, right? Wrong. All nutrients are equally essential to normal growth. Some of you know about Liebig's Law, which states there are 6 factors that affect plant growth and yield; they are: air, water, light, temperature, soil/media, nutrients. Liebig's Law of Limiting Factors states the most deficient factor limits plant growth and increasing the supply of non-limiting factors will not increase plant growth. Only by increasing most deficient factor will the plant growth increase. There is also an optimum combination of the factors and increasing them, individually or in various combinations, can lead to toxicity for the plant. Since plants use 6X as much N as P, why would we ever provide them with such huge doses of P? The popular "Bloom Booster" type fertilizer 10-52-10, provides 13.6X as much P as the average plant can use, relative to N usage. A fertilizer that provides 10% nitrogen should contain about 1.67% P, which means the middle number should be about 3.9 or 4, not 52. 10-15-10 fertilizer provide about 3.9X as much P as a plant can/ will use. When phosphorous is present in excess, it limits uptake of Calcium, potassium, copper, zinc, and especially iron. High-P fertilizers also force the grower to fertilize at much higher EC/TDS (fertility) levels than when using fertilizers with more appropriate ratios. ".... is there any effect (good or bad) from different levels of water hardness?" Unless you know what the level of hardness is, what element(s) account for the hardness, and make allowances by adjusting your nutritional supplementation program for their presence, the effects are going to be deleterious. The question is, to what degree. Most of the issue will center around a slow upward creep in pH caused by carbonate build-up, which can be somewhat resolved by acidifying your water, changing your water source, or using an acid-forming fertilizer. Do you have any questions or input? Al

From what I can see of the leaves in your photo, the plant looks like there might be insect infestation. If that's not the case, there are some good videos on YouTube on how to repot a long-necked violet. Even if it's savable, it will be months if not longer before you'd have a healthy, blooming plant again. Frankly, if this were mine, it would go into the compost pile and I'd start again.

If you're referring to the hairlike appendages they are called trichomes. Leaves and stems covered with this particular appendage are said to be pubescent. There are many types of trichomes that serve different purposes. You can find much more info (if you're interested) by using "trichomes" as the searchword. Pubescence in plants is most often a mechanism which slows water loss to air surrounding leaves. Leaves have a layer of still air surrounding them (boundary layer). When water lost through foliage is trapped within the boundary layer it raises the relative humidity within the layer. Higher relative humidity slows further evaporative loss through the plant foliage. Trichomes make the boundary layer thicker and the air within the boundary less likely to to be blown away by ambient air movement, which increases water loss. Al