"...Mist house accelerates the process of the plants? DUH! I guess
the answer is yes, but I would like to know why?.." (customer question)
HOW DO PLANTS DRINK WATER?
Water is absorbed by all plant parts. In healthy plant it works as
a pumping station: from roots - through stems - to leaves and flowers/fruits.
HOW DOES AIR HUMIDITY EFFECT PLANTS?
Two sides of the coin. High air humidity means:
USING MIST/FOG HOUSE
Mist house, especially fog-house, has nothing to do with more frequent watering. The idea of the fine mist is to create a humid air creating fine water sprays during short periods of time. Most of the water, ideally, stays as a dredge in the air and doesn't soak the soil. Sometimes mist-houses are equipped with a separate irrigation system - for watering the plants, because if the mist/fog system is made right, it shouldn't provide enough watering for a root system if any.
There are several reasons why you may use a mist-house.
1. Plant propagation.
2. Establishing bare-rooted plants.
For establishing bare-rooted plants it is important to provide the following:
Rate of misting depends on plants. Some requires more, some less. Some plants can evene recover in one-two days. Normal mist mode should be like for cuttings to start with, then in 2-3 days decrease frequency of sprays, gradually going down to "5 sec on - 30 min off " schedule in 1-2 weeks. By the end of treatment, you don't have to keep leaves wet at all times unless you see a need.
It's very important not to overwater root system. Make sure plants don't sit in water and have very good drainage. In our experience some plants are encouraged by short period (few hours) of "droughts".
3. Helping sick plants to recover.
This can be done similarly to establishing bare-rooted plants with lighter effect. Sometimes when the plant's root system is damaged by overwatering, or the plant came mail-order from a long trip, it may be beneficial to keep it under mist for a while.
Unlike bare-rooted plant, the sick/stressed plant still has some roots functioning (unless they are completely destroyed) and doesn't require long treatments. A side effect can make it worse: if you keep the plant under "pampering" mist system for too long, it will adjust to "easy living" and stop working on developing it's own vital systems. Even with bare-rooted plants, we take them out of mist in 2-3 weeks, no matter if they start complaining right away: get wilted and look dangerously sad.
We try not to pay attention to this whim and usually after the plants see no one cares about complains, they gather energy and make it. Only a few plants that don't seem to be ready after 20-30 hours out of mist, go back to the misthouse.
You have to run your mist only during daytime. In the darkness, plants don't
do that much of perspiration which means they don't lose water. Right after
sunrise, they wake up and with temperature raising, leaves get dry again.
Control your misthouse with a timer set up from approximately 6-7 am to 6-7
pm, depending on time of the year.
Remember that all you have to do is just keep the leaves wet and soil slightly moist but not soggy.
LIGHT AND AIR
Filtered bright light is the best. On one hand, you don't burn the tender leaves and keep eveporation under control, on the other hand you still provide enough light for vegetative process. Besides, brighter light kills fungus.
Your misthouse should be covered with planting all the way around. This will keep humid air in and protects sensitive plantings from undesired rain, since you need to control amount of water coming into pots. However, the tricky part is - a) you have to provide good air circulation (you don't want fungus and mold be your guests) and b) with high afternoon temperatures, the plants may get "cooked" under plastic where temperature may reach 90F and higher (critical number). Providing windows and in-window fans at the ceiling level is a good solution.
To limit amount of sun, you may use a shade cloth over the plastic (as many layers as needed) - this will also desrease temperature inside. Plastic reflecting film or paint can be also helpful.
When you plant cuttings or bare-rooted plants in a well-drained medium that is not susceptible to rot, most likely this medium doesn't have much organic in it, which means nutrients. Once your plant started to root or recover, it will continue growing, and will need not only water, but food as well. This is why we add a bit of slow-release fertilizer in propagation mix - so once the plant has a tiny root, the meal is ready for it. However, even with fine fog the soil gets flushed very soon, and no nutrients left. After the first new roots or shoots appeared, apply some fertilizer. You may add more slow-release granules like Osmocote or Dynamite, or spray with 1/2-1/4 doze of water-soluble fertilizer over the foliage once a week, at evening hours.
Using Micro-elements supplement is even more important for young and establishing plants. Iron-deficiency is a very common problem with cuttings and stressed plants.
We recommend applying natural hormones Epin and Cirkon
- soaking cuttings before propagation
- spraying potted plants - sick or after bare-rooting (in the evening, so the hormone stays on leaves overnight without being washed-off)
In addition to stimulation functions, the treatments with Cirkon will protect your plants from fungus which can be a serious problem in hot and humid environment. The propagation/potting mix should be watered with Cirkon solution once, before setting up a mist schedule.
Pre-treatment of pots/cells before potting with bleach and/or copper anti-fungicide will be useful, too (must rinse well afterwards).