Hi. I am going overseas for the last 2 weeks of July. I don't have anyone that I can ask to water my plants (or trust well enough to be in my apartment). I read on another thread about the wicking system. I will give that a try. Since I live in Houston and it's broiling hot outside right now, I was also thinking about moving the plants off my patio into my little dining area. I live in an apartment and don't have access to a water hose, so I can't set up a drip irrigation system. Would moving them inside help slow evaporation since the temp would be cooler, or would they be shocked from reduced sunlight? What about plastic bags placed over the plants like tents? Doesn't that keep the moisture in? I just don't want them to all die while I'm gone. I love my plants. Thanks for your help.
Need advice for plant survival
Moving them inside would help slow water use because of the cooler temperatures so that's definitely an option to consider. Reduced sunlight won't shock the plants--it's when you do the reverse and take things that aren't used to sun and put them in full sun without adjusting them gradually that you'll have problems. Long term if there's not enough light for them indoors then they may get unhappy, but for 2 wks they should be fine. Plastic bags are definitely not a good idea if you leave the plants outdoors, they'll act like little mini-greenhouses and cook your plants for you. Indoors I don't know if they'd help you that much and they could hold moisture on the leaves which could encourage fungal growth, so I'd probably skip them.
How many and how large?
Al
Get a small blow-up swimming pool. Place it on a large piece of plastic inside, if on carpet. Put the pots in the pool and add a few inches of water. Large pots could sit in your tub.
I used to move all my house plants into the shower when we went on vacation. We had glass doors so I'd tape a thin plastic drop cloth from the top of the door frame to the top of the shower surround. This made the shower kind of it's own closed environment. I'd put one of those flat sink stoppers over the shower drain and put about a quarter to a half inch of water in the bottom of the shower. Worked pretty well.
Marilyn
Tapla,
I have a 20" tree hibiscus, a few 16-18" pots (plumeria, bougainvilea, Angel's Trumpet, coleus, geranium. I have a few smaller pots with various plants in them.
I was thinking the bathtub. What about no sunlight for 2 wks? I have some kind of halogen light in my shower. Will that at least keep them alive?
I like the idea about the blow up swimming pool. Thanks.
No plastic bags - makes sense about the fungus.
Thanks for all of your suggestions! I really appreciate it.
The swimming pool idea is good, but two weeks in standing water will rot the roots of all or almost all of your plants. I would get a rayon mop-head & pull strands from it. Insert the strands into the drain holes (1/plant). Set the plants on something of uniform height (bricks, bowls?) and fill the pool so it is deep enough that the water won't evaporate while you're gone, but not deep enough to touch the soil in your pots. IOW, your pots should rest slightly above water level. The wick should dangle in the water where it will soak up enough water to keep your plants alive.
Be sure to leave a window cracked or the air cond on low because a swimming pool will add a LOT of humidity to the air & you don't want the walls dripping/absorbing sweat.
Other things to expect: Some of your plants will lose lots of foliage if they are moved from a bright location to one with considerably less light for 2 weeks, but it will grow back. Your plants will likely need some period of readjustment to full sun after a 2 week stay indoors, so don't just move them outdoors into full sun when you return - take your time.
Al
Tapla,
How far will water rise in a rayon mop thread, and what's the maximum distance from the water level to the bottom of the pot?
I think you should probably test the wick to see how high it pulls water, because it varies slightly from one (rayon) material to another. I wouldn't trust the wick to pull water any higher than 3-4 inches, even though it will probably pull it higher; so the water level at its lowest should probably be no more than 3" from where the wick contacts the container medium. Of course, experimentation and discovering the ACTUAL limits is always best.
As I think on it further, perhaps more than 1 strand per pot would be more effective in this application.
Al
It's hard for me to reconcile the physics you[ve described so well previously. On one hand, a wick can serve to vector the force of gravity to overcome the cohesive or capillary force of the soil on water, to pull more water down and out of a pot, increasing the root zone. On the other hand, the cohesive or capillary force of a wick can overcome the gravitational force, and pull water up into a pot, so the root zone has water to support the plant.
There must be an equilibrium state in there somewhere, I just can't keep even the rough equations straight in my head today.
The easiest way to think about it is that the wick will work to transport water from a place that has more water to a place that has less water. When you have a wick hanging down out of a pot to help drainage, you don't have a bucket of water sitting at the other end, the wick would just be suspended in air so the wick will transport water out of the pot since the soil is wetter. On the other hand, when one end of the wick is sitting in a bucket of water, then it's going to transport water in the opposite direction from the bucket of water up into the soil which has less moisture.
How it drains a pot: When the media supports perched water, the wick 'fools' the water into 'thinking' the pot is deeper than it is (it increases the gravitational flow potential [GFP]). The water molecules in the perched water table (PWT) move down the wick, searching for what they 'think' is the bottom of the container and get pushed off by the water moving down from above them. The water that is tightly held within soil particulates cannot be pulled from the pot because it is tightly held by capillarity against the gravitational flow potential. Ergo, a wick only works to varying degrees, depending on how tightly the water is held (works well in soils with low PWTS, but works poorly in, say clay).
Using it to water a container: When we consider how wicks ADD water, we need to consider the strength of the capillarity of individual soil particles. It's not a big stretch to envision that if a wick is not strong enough to pull water tightly held within soil particulates out of those particulates, that the capillary pull of those particulates are probably strong enough to pull water from the wick. If we trace the path of a single water molecule from the reservoir upward into a dry soil, we'll see it being pulled up the wick against the GFP. When it reaches the soil and contacts a soil particle with greater capillarity than the wick, it moves from the wick to the soil particle. It moves from soil particle to soil particle 'looking' for the greatest capillary pull. Since dry pieces of bark and peat have lots of pull, the water is pulled away from the wick and diffused throughout the soil.
By illustration as opposed to scientific description, we would see the water in a drainage situation evacuating the largest pores (macro-pores) but remaining in the smallest pores (micro-pores), most of which are within soil particulates. Using the wick in absorption mode, we would see the water entering the container via the wick, and then moving from particle to particle, filling the micro-pores but leaving macro-pores air-filled.
Barring evaporation and plant usage of water, there should be a near stasis in the two application, but the wick-watered pot will never hold quite as much water as a pot at container capacity (just drained) because once a pore is filled with water, it is reluctant to give it up. This part of the equation comes from the cohesion factor - the tendency for water to stick to itself.
Al
This message was edited Jul 9, 2009 4:01 PM
Fair to say that a free-hanging wick will lower the PWT to about the level the same wick in a water reservoir would raise it?
Seems to me even if the bottom end of the wick is in water, it can still lower the PWT. The difference between PWT in the pot with a wick end IN water vs wick end OUT? Not much, I'd think.
The cohesive force exerted by the reservoir water touching the tip of the wick would cause it to pull MORE water out of the soil than with a dry wick-end. But, with reservoir water available, there'd be no net loss of in-wick-water due to evaporation, which would cause the wick to pull LESS water out. A plus and a minus, for almost no difference?