I believe that the most important thing when mixing a hoya substrate is finding the one that will work best with your conditions. Different growers keep their hoya plants in all kinds of substrates, everything from 100% soil to entirely soilless substrates such as leca or pon.
I would say nothing is good or bad per se. It just depends on how you treat the substrate: how often do you water, how much air humidity do you have, whether you keep your plants indoors or outdoors, etc. So I would advise you to play around a bit and find the perfect blend for yourself. Everything gets so much easier when you do!
New hoyas – to repot or not to repot?
In the past, I used to keep my newly acquired hoyas in their original substrate for a few weeks after I got them. I don’t do this anymore. I know that many growers speak against this, but I now repot every hoya as soon as I get it. Why?
#1 Hoya roots can rot really quickly in transport. Especially if they arrive in wet soil. By repotting right away, you have a chance to inspect the roots and treat any damage while still manageable.
#2 Hoya roots can also rot fairly quickly if you keep them in a substrate that you are not familiar with. Even when the substrate looks nice and chunky, you still can’t be exactly sure when to water. This used to drive me crazy. Is it time yet, do I wait some more, what do I do??! You don’t want to water too soon (to avoid root rot), but you also don’t want to water too late (to avoid losing delicate new growth). I know my standard mix very well and I can tell from the weight of the pot whether the hoya needs watering or not. By repotting the plants right away, I can always be sure about my watering schedule.
One potting mix to conquer them all
I keep all my hoyas in the same potting mix. Not only that, I actually keep all my plants in the same mix! The same substrate blend that hoyas like works very nicely for aroids as well. Which makes perfect sense, doesn’t it? No plant wants to live in soggy, water-logged soil with no air! Hoyas just show it sooner because of their thin roots.
Using the same substrate mix for all plants also makes it easier to repot each individual plant exactly when needed. No special preparations are required and no need to repot plants in batches. I keep 30L of the potting mix in a storage box in my hallway, repot on the spot when needed, and simply refill when it is gone.
I will not go into all the different possibilities of substrate mixes, because I am sure you can google this yourself. 🙂 I will just let you know what exactly is in my mix:
- ⅓ perlite 2-6mm (10 L)
- ⅓ coconut coir fiber (10 L)
- ⅙ orchid bark (5 L)
- 1/12 soil mix for green plants (2,5 L)
- 1/12 leca balls (2,5 L)
The size of perlite is 2 – 6 mm because this is what I can easily buy here. I use the coconut coir fiber which you buy in a block and add water to it before blending in a mix. I buy orchid bark and soil mix for green plants from Compo. I tried some others but these I liked the most.
OK now, the coconut fiber, perlite, and leca are usually sterile. However, with soil mixes and orchid mixes, you can very easily acquire a free colony of the annoying fungus gnats. The substrate is moist and it sits in the garden center, so this is just perfect for those little fuckers to move in. To avoid infestation, I always bake these two substrates in the oven before blending them into my mix. 20 minutes at 150 degrees Celsius and no fungus gnat will survive. And I love the smell of the baking soil!
After this cools off, I mix all the ingredients together. Here are the steps so you can imagine it better:
- Add 1/3 of perlite:
2. Add 1/3 of coconut coir fiber:
3. Add 1/6 of orchid bark:
4. Add 1/12 of soil mix for green plants:
5. Add 1/12 of leca balls:
And this is the final result:
The mix is very chunky and airy. It does not hold too much water, but still holds enough of it so I don’t need to water the plants every other day.
Have I tried switching the substrate to something else? No, until my hoyas are happy, I go by ‘don’t fix it if it ain’t broke’. 🙂
As already mentioned, the size of the pot is also very important! I believe it is optimal for hoyas to dry out in a week after watering, tops. Some of mine are thirsty every 3-4 days. If they dry out in less than 3 days, it is usually time to repot to a slightly bigger pot.
Green is the colour 