Shop for Grammatophyllum & Other orchids
Grammatophyllum are tremendous, large-sized orchids that are native to the Philippines. They have grown in popularity due to their 2 to 3 foot tall flower spikes that each bloom with 50 to 100 flowers! The summer to fall blooming period is equally as spectacular, typically lasting 1 to 2 months.
Light and Shade
Grammatophyllum need abundant though not intense light in order to grow and flower well. Growing in an east window is ideal, as the early morning sun is very important. However, a south window will also be suitable, so long as the plant is provided with light shading from the middle of February to the end of October using a sheer curtain. Grammatophyllum can be grown outside from June to late fall in areas with filtered light, such as through a pine tree or shrub in early morning or afternoon. Be careful not to exposure these orchids to prolonged direct sunlight, as the leaves may sunburn. If using artificial light to grow indoors, LEDs are the best option for Grammatophyllum. The artificial light market has expanded greatly in recent years, so a quick Google search will result in a variety of lighting options and price ranges.
Temperature and Humidity
Grammatophyllum thrive with a day temperature range between 72°F and 85°F (22°C to 30°C). At night there should be around a 10°F (6°C) drop, to around 65°F to 75°F (18°C to 24°C). This lower night temperature will help initiate flower buds and promote stronger growth. Grammatophyllum benefit from humidity levels between 45% and 60%. This can be achieved at home with the use of a humidifier or a humidity tray. Just make sure that the plant is not standing in water or the roots will rot.
Watering
Water frequently and heavily during the growing season, especially when the spikes are emerging. During winter months, this plant can be kept slightly drier, but watch the leaf tips. If they turn brown and shrivel, it is a sign of underwatering. This plant also has pseudobulbs at the base of the leaves like a Cymbidium. The pseudobulbs should be plump in the summer or just slightly shriveled in the winter. The pseudobulbs are also a guide in your watering practices. Increase watering as the pseudobulbs begin to shrivel. We always recommend watering in the morning, as this gives the leaves time to dry and avoid bacterial growth overnight. If possible, use water low in alkalinity, such as rainwater, distilled water, or reverse osmosis water. If you have a dehumidifier in your home, the water that collects in the tray is excellent for watering orchids.
Feeding
We highly recommend Green Jungle Orchid Food, specially formulated to provide orchids with the nutrients they would naturally encounter in their wild habitats. This is the fertilizer that we developed to use on our own plants in production, with excellent results for decades! This formula works best with water low in alkalinity (such as rainwater, distilled water, or reverse osmosis water). However, you may use tap water, keeping in mind that mineral buildup will require repotting more frequently, on the order of every 1 to 2 years.
If potting in bark mix, fertilize every time you water during the growing season, flushing with non-softened water once a month. This rinses the media of salt and mineral buildup. During periods of inactive growth, fertilize every other watering. If potting in sphagnum moss, fertilize every 3rd watering year round.
Potting
At Orchids Limited, we recommend potting Grammatophyllum using New Zealand Sphagnum Moss or the Medium grade of our Traditional Orchid Bark Mix. Large Grammatophyllum specimens can utilize the Large grade of our Traditional Orchid Bark Mix.
In general, repotting should be done every 2 years in the spring. Repotting becomes necessary when the plant has outgrown its pot and the new growth reaches out over the edge, or when the potting medium has broken down. When repotting, choose a pot that is large enough to accommodate 2 or 3 years growth (1 or 2 new pseudobulbs per year). Grab the plant near the base of the pot and start by gently, but firmly, pulling the plant out of its old pot. When growing in clay pots, it is sometimes easiest to simply take a hammer and break the clay pot. Do not worry about breaking or cracking roots, this will not harm the plant long term. If the mix is old, crumbly and sour, carefully remove the media and rinse the root system. Trim off any dead roots and dead pseudobulbs. Position the plant with its oldest pseudobulbs to the edge of the new pot. Then, spreading the plant roots out, fill in the space with the potting medium. Press down firmly with each handful so that the plant does not wobble around. Build up the compost until the plant rests with its rhizome on the surface, about a half-inch below the rim of the pot. If your newly potted plant is wobbly, you can use a ring support or rhizome clip to secure the plant.
To divide a Grammatophyllum, cut through the rhizome between the pseudobulbs, leaving three to four bulbs per division. Try to untangle some of the roots for each division. You may have to cut some of the roots in order to divide the plant. You can watch our video on dividing orchids here.
To avoid the transfer of orchid diseases, it is standard procedure to sterilize all cutting and potting instruments before using them on a plant. This can be done by flaming pruning shears with a butane torch, or by spraying with rubbing alcohol and wiping with a clean paper towel.