Masdevallia orchids are cool growers. They love a cool, moist environment with plenty of air movement to remind them of their origins in the high country of South Americia. They do no have pseudo bulbs like many epiphytic orchids, only fleshy leaves to hold water and nutrient. One should be careful therefore to maintain moisture at the roots and in the environment. It is still important not to over water, never keep the medium soaking wet. For the reasons above, it is vitally important to keep the growing medium sweet. If it decays it will rot the fine root systems and the plant will collapse. For this reason we recommend repotting annually.
Potting mediums should be either good quality aged pine bark sieved and graded, Sphagnum moss or more recently coco coir fibre. Our favourite method is to use 1/3 to 1/2 pot of ark then add the orchid Osmocoat then top off with Sphagnum moss. We find this allows good drainage while still maintaining the benefits of Sphagnum moss that Masdevallias relly like. The Osmocote maintains excellent nutrition for the plant betwen annual repotting.
In the past year good quality coco coir fibre has become available. We are currently potting many plants in this medium and feeding with Orchid Osmocote, which as usual we place in the bottom 1/3 of the pot. Results look promising with easy watering while the fibrous nature of the material assures plenty of air to reach the roots.
Masdevallias need to be well shaded in Summer to keep the plants cool and the environment humid. If possible try to keep the temp. under 30C, a few hours warmer won't matter as long as you have humidity. Constant dry heat will cause the plant to drop its leaves and collapse. In Winter try to give bright airy conditions, humidity is usually high any way. Some overhead cover is essential in Winter or they may become too wet. Minimum temperature should be 5C for most, whough be aware there are some warmer growers. Masdevallias will sometimes tolerate a light frost but try to avoid this if at all possible.
Cool, moist, airy conditions free from frost. Avoid hot and dry. Pot annually, do not divide too small. Feed Osmocote or Manutec Orchid food. Keep free from pests especially Aphids. Do not overwater.
Masdevallias may be grown indoors if you have light