By Serena Roman ·
Shade vs. Sunlight
How much sun does a Vanda orchid need?
Strap-leaf Vandas require full morning sun from about 7 to 10 a.m. and protection from direct sun in the hottest part of the afternoon. At Lady Vanda Orchids in Ocala, Florida, the Vandas for sale grow in a shade house under 30–50% shade cloth. Fertilizer supplies mineral nutrients, but light powers photosynthesis, which produces the sugars the plant uses for growth; a Vanda that receives too little light cannot make full use of the nutrients it is given. Strap-leaf Vandas can be acclimated to full sun, but only slowly — and because the sun's path shifts with the seasons, a spot that works in winter can scorch a plant in summer.
Sunlight provides the energy a Vanda uses to produce sugars through photosynthesis. Fertilizer supplies mineral nutrients, but without adequate light to drive photosynthesis, the plant will not grow optimally and may decline over the long term.
We keep most of our personal collection under a covered deck with 50% shade screen on the northwest-facing side to filter the mid-afternoon sun; 50% is the upper end of the 30–50% range we recommend for Vandas. This method has worked well for all of our orchids, from Vandas to Phalaenopsis, Cattleya and Oncidium. It should be noted that as the seasons change so do the patterns of the sun in reference to your property. A position that may work in the winter season may not work for summer. I have seen growers scorch their orchids because they have not noticed the change in exposure to sunlight.
Lady Vanda Quick Tip
Ideal morning sun window: 7 am – 10 am · Shade screen: 30–50% · Avoid direct afternoon sun at the hottest hours · Re-check exposure each season
Fertilizers
A search for 'orchid fertilizer' returns a large number of products, and the choice can be confusing: liquid or powder fertilizers, or a small bag of Osmocote slow-release pellets tied to the basket. Fertilizing orchids is just as personal a topic as asking someone what their favorite orchid is. Once a person finds something that works for them, they do not want to deviate from the proven method. There is nothing wrong with this approach, but it is worth experimenting with different brands and N-P-K (nitrogen- phosphorous- potassium) values.
Most fertilizer labels call to use once per month at a specific rate. However in almost all cases it is better to fertilize at lower doses more frequently so that your orchid receives a consistent supply of nutrients at all stages of its growth cycle. Unlike some orchids, Vandas are usually in a consistent growth cycle and will show blooms, root growth and leaf growth simultaneously. All of this takes enormous energy from the plant to maintain, so consistent fertilization supports the process.
How often should you fertilize a Vanda orchid?
What We Use at Lady Vanda
Fertilize Vandas weekly at a low dose rather than monthly at full strength. At Lady Vanda Orchids in Ocala, Florida, Serena Roman fertilizes the Vandas, like every plant in the greenhouse, Peters Excel 15-5-15 CalMag Special at 1 teaspoon per gallon once a week, dropping to every other week in winter. Vandas are almost always in active growth — making roots, leaves and flower spikes at the same time — so steady small doses keep up with that demand better than one large monthly dose. The added calcium and magnesium matter most with reverse-osmosis (RO) water or collected rainwater, which supply almost none. If you water with tap water, flush the root zone periodically with rainwater or RO water to remove accumulated salts.
Most growers can use tap water and a generic orchid fertilizer and their plants will grow adequately. A more deliberate water and fertilizer program, however, can produce exceptional results.
