Watering Orchids in
Horsemanure
It is important with orchids potted in horse manure to make sure the pots are able to drain freely and to water them often.
Nic used drip irrigation and turned it on every day so some water drips out the bottom. Some books advise to keep the roots fairly dry but take no notice of this. If you have any doubts, try a few dryer plants but you will soon see the performance of the well watered ones.
The plant is provided with nutrients from the horsemanure by the water which passes through the horsemanure and is then taken up by the roots.
Nic was often asked whether daily watering may leech the nutrients from the medium. With his drip irrigation system the horsemanure medium is uniformly wet before it drips out the bottom. If you use a system like this or a very slow trickle system, you can turn it off before much water drips out the bottom of the pot so there won't be much leeching of nutrients from the medium. Of course there is some leeching but not enough for it to be a problem.
Strength of Solution and Quantity of Water
The strength of the solution available to the plant is linked to the quantity of water you give it. You can use pure water and this water will pick up the nutrients from the horse manure to feed the plant. If you give less water, the solution will be more concentrated and for plants that like a weaker solution (lower E.C. values) this is a problem. For these plants, see also the page Potting Info.
The horsemanure does not need replacing until the plant has out-grown the pot as shown by the photo on the page 'Roots Photo'.
Another point to mention here is fungi. The plants should be dry before night fall to avoid fungi problems, so make sure watering is done early enough in the day so there is good drying time before night. It doesn't matter if they become wet again during the night e.g. with automatic watering, as long as they are dry once a day the fungi spores shouldn't develop. Also concrete or plastic floors tend to promote fungi problems when they don't drain excess water away and dry off.