Dendrobium Potting Medium Advice
 

Hi ive got 4 dendrobiums i was wondering if potting them in sphagnum moss would be suitable ? they are currently growing on my windowsill in the pots they came in how ever they dont really have any medium just some bark that they are growing round.

what would you suggest i use to repot them ?

many thanks
Craig

Hi Craig,

Potting mix really depends on your watering schedule and your growing conditions, so it's hard to give good solid advice, unfortunately ;) I find that bark stays dry too long in my conditions, so I use chunks of coconut - people growing outdoors in humid hot conditions with regular rain may recoil in fear at that advice - some of them grow in gravel and get spectacular results. Generally, water retention goes by the following order:

Sphag > Coconut husk > fine bark > medium bark > large bark > inorganic rock/gravel/clay

*usually* dends don't do well in sphag in most conditions, but I have one in sphag that enjoys itself, so no hard and fast rules. Just make sure you let the sphag get dry-ish in between waterings!

(Also depends on the type of dend you have and the season of course!:faint:)

thanks for the quick reply and the advice Calvin,

Im watering once evry 7-10 days or just as the sphag becomes almost dry which ever comes first and im only watering enough that the spahg becomes moist and not so its sogging as i dont want to rot the roots my Growing conditions are just in the home on a North East facing windowsill its the best I can achieve as my house is on a corner I originally bought them as Seedling from East coast orchids and they have grew quite a bit since in only 2 weeks :) Im also using Orchid fertiliser on a weekly basis when watering but at only 1/4 of the strength.

Craig. Take care with spahg as it can be quite unforgiving if organic ferts are used.
Think about where the dendrobs naturally grow sometimes certain plants prefer slab culture rather than being grown in a pot. In NZ we would use a small amount of spahg to allow the roots to maintain moisture until they have hold on the slab then mist as required. Also remember that Fert builds up salts on the roots that when left to dry can burn the roots so every second week just water I find works well.

If the potting mixture is bark, you need to use a bit more fertilizer, especially a bit higher N, during the growth period.

If you use spha moss, you need less fertilizer and watering.

There is no standard answer. Many people grow Den. in spha moss and get much stronger plants than growing on mount, due to moss' ability to retain more moisture and fertilizer. However, if the water or fertilizer is too much, growing in moss can lead to rot easier.

If your Den is growing in bark fine, I would recommend to keep it there and just add some fertilizer. Depending on humidity, you may increase your watering frequency. Baiscally whenever the bark is totally dry, you can water. It depends on the species as well. Some prefer to be watered when just the surface of bark is dry, while some others prefer the bark to be completely dry during watering.

Good luck!

I have 6 different "dens" that that I keep pooted in a mixture of bark,lava rock and perlite. This mixture works out as it does not retain water for a long time and the roots get a substantial amount of air.