Water
Many hoyas are succulent in their growth but most of them grow in tropical areas where a daily rain shower is common. That means that restricting the watering too much won’t make them grow optimal. I have had huge success with quite the opposite method. Instead of watering the hoyas with a watering can I take them to the bathroom and give them a lukewarm shower, leaving them there for at least an hour. That gives the soil enough time to get rid of the excess water and the plant will benefit from the damp air during that hour. I repeat this twice a week for up to a month. This will give them a real boost!
There are of course exceptions like the H. pachyclada where the leaves may crack if given too much water, see picture to the right. H. australis ssp. rupicola and H. australis ssp. oramicola also have very thick leaves and will benefit from dryer growing conditions.
To the left is a picture of a plant of H. australis ssp. oramicola where the stem has suddenly started growing with long internodes instead of the typical dense growth.
Fertiliser
There are as many views on fertilisers as there are manufacturers of the stuff. I went to a lecture with a Swedish botanical professor - Tom Ericsson - that said that his studies showed that a weak solution of a common Swedish brand (Blomstra) is the best product on the market - and the cheapest! The trick is to give the plants a weak solution every time you water your plants. All cells in the plant has the same needs and in order to grow, that is, create new cells, the plant needs food. 1–2 millilitre for every litre of water is his recipe
for success. In order to be able to pick up the elements the plant needs water, which is yet another reason not to keep the plants too dry. . I keep the fertiliser in an old washed out soap dispenser and have measured how much one squirt is and then it’s easy to measure out the exact amount every time I water. In the table to the right the optimal levels of macronutrients according to Ericsson are shown. If you want to know how to calculate your brand in comparison click on the picture for an example.