Yellowing is usually a sign of overwatering or underwatering. All of those hoyas you mentioned (except for curtisii and the NOIDs) like to be kept on the moist side, so my first guess would be that you are underwatering. I would not let lacunosa, multiflora, and bella dry out between waterings - mine are kept consistently moist.

Have they been fine in the past with your current watering schedule, or has this been a recent change with the cold weather? Are they near a draft? Also, I would be careful using a fertilizer this time of year. Even though you are using 1/8 or 1/4 of the recommended amount, that may still be too much if you are fertilizing every time you water. With regular fertilizer (instead of something weak like Eleanors VF-11), I would only use 1/8 or 1/4 strength with every watering in Spring and Summer....not in Winter. So I would definitely either cut down to no more than once a month - or stop fertilizing altogether until Spring.

Other things that should be considered:
-The type of water you are using (i.e., is it straight from the tap?)
-Are you flushing the medium every few waterings so that there is no build up of fertilizer?
(I'm not sure if these 2 things would cause yellowing or dropping of leaves, but it's something to think about)

Good luck :)

Gabi

This is the time of year it's easy to overwater, but I'd agree that it's more likely underwatering with the ones you mention. Do you keep your Hoyas in from the windows or close to the glass? If close to the glass, they probably need more frequent watering (depending on how many sunny days you have...) Also, how warm you keep you house will make a difference. But I'm sure you know these things.

I use coir, too, and I DO like the way it keeps from compacting around the roots. But I find that watering is a bit different than with standard potting mix, which you can water and walk away from. With my Hoyas, I take them to my kitchen sink, water until it runs out of the bottom (BTW, I use RO water with VF-11 and hydrogen peroxide every watering...) I let it sit about 15 minutes, then I repeat that process. I think with the first watering, it tends to run through fast and there are probably a lot of spots that don't get good and wet. Once it's had a chance to "take up" some of that first watering, the second one hydrates some of those other spots. I don't let any of my Hoyas get too dry (though, obviously, they do take less water in winter.) This has worked really well for me since I started using coir.

Denise in Omaha

Denise,
I used hyrogen peroxide *occasionally* a while back (in addition to Eleanors VF-11), but just kind of stopped using the peroxide. What kind of differences do you notice with the HP? I know it's supposed to let more oxygen in (or something like that), but I was just wondering if there was noticeable improvement when you started using it. How much do you add to a gallon of water (in addition to the VF-11, which I add 4 capfuls of)?
Thanks,
Gabi

By the way, Nova - you might want to try misting the foliage of the hoyas that are doing poorly. Try misting several times a day (at least for now, until you see improvement). I think if you add Eleanors to your mister bottle it will help a lot. Just a side note: In the Spring/Summer, I also add several drops of GSE (Grapefruit Seed Extract) to my spritzer to keep the bugs at bay - I think it does a great *preventative* job.
I will add a link to the online store that I get my Eleanor's from, in case you are interested (he JUST raised the price slightly...from 7.99 to about 8.49...but you get a bonus bottle for free). You get one bottle of 16oz and one free bottle of 8oz.

Here is a link that might be useful: Reed's Greenhouse

Gabi,

I can't exactly say that I see a big difference using peroxide in my water with the Hoyas, but when I started using it on my Haworthias, which are famous for losing their roots, I found that problem almost ceased. So I figure if it improves the root health of one plant, it's probably doing so with all of them. I think it's probably especially helpful with the EA plants that I can't change to my regular soil. That soil is so awful, any help the roots can get is certainly in order...

Anyway, I put my water in half-gallon jugs and use 1 oz. of peroxide and 1/2 oz. of VF-11. I also use the VF-11 in my spray bottle, so they get fed both ways.

Denise in Omaha

That makes sense...I will try that for my EA hoyas. Thanks!

Gabi

I thought I had responded to this, but I guess not.....lol. I do mist quite often, a couple times a day. I have also used hydrogen peroxide at times, hubby knew of that trick. So I watered this past weekend, and the yellowing has started again. This time on my bella....and my kerri. Maybe pics will help. I do let the water flow through the bottom at every watering.

Thanks for the opinions. I hope these guys stop doing this.

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I really don't know what to think, except maybe only mist once a day. I agree w/ Gabi that most of the Hoyas you mentioned are some of the Hoyas which like things more moist. Of those I currently only grow Multiflora & I try not to let that one go dry.

At the end you mentioned Kerrii, that one definately likes to dry out btwn waterings, for sure. Sometimes they'll just yellow a leaf or 2, not uncommon on the baby leaves, I don't know why, but I lose baby leaves from time to time. Just that kind of yellowing, drying out as you've show in the pic.

I'd also stop fertilizing altogether (have always heard it's useless to fertilize ailing plants).

Are there any cold drafts (or blasts of heat) near the plants?

Good luck w/ it!

How about light? Could it be too low a light situation?

The kerrii sits on a window sill in an east window. The windows get pretty icy this time of year. There is also a vent under neath this sill. The other, like the bella, are in the same area, not against the window, but under florescent lights as well for an extra boost. All of my plants are in the same area/corner, and only a few are doing this. I have not fertilized for about a month now.....I am doing straight water now until spring (I do on occasion use VF-11)

I wouldn't mist too often, especially since I see you're in a cold region. Misting isn't bad, mind you, but too much moisture in winter can make a breeding ground for mold. I mist the Hoyas in the house when I water them only. The ones in the GH, I'll mist more often, but only when the sun is shining on them so they dry out quickly.

And like PG said, kerrii is one of those that tends to drop baby leaves, especially this time of year. I always hope for mine to go dormant so I don't end up with those long, leafless, stiff vines...

Denise in Omaha

I recently purchased Hoya Cumingiana. I watered it for the first time since I got it and I had 2 leaves toward the bottom yellow. Does anyone know much about watering Cumingiana? This hoya is new for me. Thanks
Shanna

Hi Shanna5,
I have 2 Hoya Cumingianas and I have killed two others so I have learned that they like to dry out just the same as the Hoya Kerrii and since I have been doing this my Cumingiana is now about 2 foot tall and shooting out new branches everywhere so I hope this helps....Karen.....

Yes, that helps with Cumingiana and also kerrii since it is also a new aquisition for me as well. thank you

So can someone tell me what exactly Elenors VF-11 is and also what does hydrogen proxide do for your plants. I'm in the dark.
thanks shanna

Shanna,
VF-11 is basically a plant food/mineral supplement, with very low NPK (.15-.85-.55). I also use it as a foliar spray in addition to watering with it. It's weak enough that you can use it with every single watering, all year round. It works WONDERS!

As for hydrogen peroxide, it helps to add oxygen to the roots.
Check out the link below and look at the post by ACAgapeplants - it's everything you need to know about hydrogen peroxide for plants.

Here is a link that might be useful: Hydrogen peroxide

Does Lowes carry VF-11??
shanna

No, Lowes doesn't carry it. You'd have to go to a store listed on her website (those are the places that *may* sell it) - just do a google search and you'll find her website. But I had no luck in my area with those stores. I get mine online. There's a link on one of my posts above of the online store I use, but there are other places as well.

Gabi

Gabi
I went to Reed's Greenhouse and was going to purchase the VF-11 and some small plastic pots and the shipping was more than my order. I couldn't believe it, it was like 11.50 or something.

shanna

Yeah, I noticed the shipping went up. I tried to buy 2 of the VF-11 packages several weeks ago (thinking I'd save some money by doing so), and the shipping price was double what it would have cost to buy one! You'd think they'd somehow combine shipping and not just double it. I might get it elsewhere next time.

Shanna,

If you've never done this, go to Eleanors VF-11 directly & see the notice that for $3 (presumably for postage), she'll send you a sample bottle (very generous at 8 oz).

It's certainly enough to try for a while (if you haven't yet) & perhaps enough to tide you over 'til you find a cheaper or closer source?

If interested, search for Eleanor's VF-11 for the mailing address & instructions. Just a thought.

After a difficult time getting it last Spring & it being back ordered from Charlie's Greenhouse, I was sent a box of bottles of the several different sizes. I've given the smaller bottles to other gardening friends. So I've got enough probably for this year; am esp. glad to know given what you folks are saying abt increased shipping prices. What a shame.

I used to buy it 4 gallons at a time from Eleanor, which ended up costing me around $20/bottle. But you can get one gallon from Charley's Greenhouse Supply for $24.95 + $8.95 shipping which makes it 26 cents/ounce. Buying one of those 16 ounce bottles ends up costing $15.30 w/shipping, which makes it almost a buck an ounce. My sister now carries it at her nursery about 30 miles from here, so I get it from her by the gallon these days. If you have a lot of plants and use it all the time, it goes fast. I go through about 2 gallons a year.

One suggestion though... Pouring out of those big gallon jugs is a hassle and sloppy. I keep an old dishwashing soap bottle full of it along with a shot glass on a shelf in the GH so it's handy to put in my water every time.

Anyway, here's a link to Charley's.

Denise in Omaha

Here is a link that might be useful: VF-11 at Charley's

Call around to your local drug stores or Hardware stores. I have found it at Ace hardware, Longs Drugs, Rite-Aid Drugs, Save-On, and CVS. The Longs Drugs has it in the gallon containers even. Since I have been using the "beer fertilizer" to water with, I only use the Eleanor's as a foliar feed when I spray them, so I am not going through so much of it as I used to. I have also cut out any fertilizing of all the outside plants and just lightly do the inside ones that are under lights as everything else has gone into a winter shut down mode. (Including me...ha ha)
Marcy
Marcy

Denise-
Thanks I just ordered from Charlies Greenhouse.

Mairzy-
Next time I need it I will definately look at that drug stores. I wonder if it matters what time of year if they carry it?? Thanks for the info.

shanna

Yeah Denise (hi!!!), the pricing you spoke of at Charlie's sounds like the deal I made, something like that. I've been using it at most waterings, so I am going thru it fast.

I have some Sans Cylindrica sprouting that's looking exceptional & somehow, I think it's the VF-11. I also have a new Anthurium (which usually give me a lot of trouble), doing very well & I'm wondering if it's the VF-11. Hard to know.

I even have a Euph. Lophogona setting buds (for the very first time), right next to the window & it's in the low 30s here now -- who knew?