The soil will indicate whether the plant needs to get watered again. Also, succulent leaves will help you determine if your plants have been neglected. A good soil is the best thing for Crested Euphorbia. The plants can feed off those nutrients for quite some time but eventually the nutrients run out and will need to be replaced. But humidity is more important in dry or warm conditions. The soil will also dry out quicker. In fact, the soil and the pot I used to grow these 4 portulacariasafra variegata was the same as the one I used to make the regular elephant bush.