Dr. Bill's Orchids, LLC Culture Guide- Dendrobium (general)

Before starting specifics, it should be noted that the Dendrobium genus is very diverse in care needs as there are 4 main groups (Sections) of these plants. The following guide is a GENERALIZED care guide for Dendrobium types. Please see the specific guides for Section breakdown

Light:

Typically, east-facing windows are a gold standard for lighting to get good, bright light until midday, with filtered light afterwards. South or West windows can also work, but care should be taken to have a slight filter of this lighting to minimize sunburn (sheer curtains are a great help for this!). For those in USA/North America, you may have best flowering after putting plants outdoors in a bright-shade area, no direct sun! Anything stronger than bright shade (think the filtered light under a tree, filtered light through latticework or shadecloth) puts your plant at risk of sunburning.

Temperature:

Overall, Dendrobium are intermediate-warm growers (with some exceptions). Overall temps should be 70-85F during the day, and 60-65F at night (ideally a 10F day/night temp difference). 

Humidity:

Medium-high humidity (50-70%RH) often lead to best growth and presentation of leaves and flowers. While not 100% necessary, these 50-70%RH conditions will give the best/maximal growing conditions and presentation of flowers. In addition, it can help your flowers last a little bit longer. In order to get this boost in the home setting, humidifiers are a great supplemental option. Setting the plant on top of stones with a bit of water can also be beneficial, but need to make sure that the roots are not sitting in any water -> can lead to root rot. 

Water:

Dendrobium like to dry a little bit between waterings, media should be just baaaarely damp or even dry to the touch before watering again. This group of orchids are tolerant of going a little on the extra-dry side, but this will lead to canes to shriveling, which is a less than ideal growing and presentation quality. Ideally canes should be relatively plump on average when watered appropriately. During active growth season, they should be watered frequently, and during each watering, the growth medium should be thoroughly saturated. During the "rest/semi-dormant" periods (depending on type), you may need to cut back on watering, as plants will not take up as much water compared to fully active-growth months.

Watering in the morning tends to give best results for home growers to allow plant leaves to dry out before the cool temperatures of night -> on occasion, wet leaves and cooler temperatures can lead to several forms of rot/fungal issues.

Fertilizer

We recommend a balanced fertilizer (where numbers on the back/side labels are approximately the same 10-10-10, 20-20-20, etc). Bloom boosting fertilizers are not necessary for culturing these plants. If potted in sphagnum moss, plants may need an occasional flush to minimize fertilizer salt buildup in the rootzone. For dendrobiums that have a dormancy/winter rest period, fertilizer should be decreased or stopped altogether.

Potting

Dendrobiums are tolderant of a wide range of growing media, often seeing them planted in medium-size fir bark mix, or even in pure sphagnum moss. Which media is better? It depends on your growing conditions and your watering regime at home (see watering above). Plants in sphagnum usually need to be watered less than those in a bark mix. Repotting should be done every 2 to 3 years in the spring/summer. 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 (2 to 3 new canes per year). Trim off any dead roots and dead canes. Position the plant with its oldest canes to the edge of the new pot. Then, spreading the plant roots out, fill in the space with the potting medium.

Pests

Largest pest issue for Dendrobium is usually mealybugs, which will hide in all the nooks and crannies of the plant, especially where the leaf attaches to the cane. Mealybugs can be controlled with a spray of pure rubbing alcohol (usually 70%), rubbing alcohol + some a few drops of dish soap, or commercial pesticide sprays if there are large numbers of them present.