Water

I'm trying to make an automatic watering system for my plants. The main reason I want to do this is to regulate how much water my plants are getting. Keeping that in mind, an ideal system would allow a different amount of water output for each plant. Each plant has different water requirements which depend on the size of the plant and the type of plant it happens to be. An ideal system would be difficult to build, and I'm building a system that's cheap and consists of some recycled parts. So, I'm shooting for the simple alternative - a watering system that satisfies the water requirements of the plants in my collection that use the least amount of water. Then, I could simply supplement the remaining water manually. You could make a good argument that I want this system because I'm lazy, but if that were the case, I wouldn't bother with plants at all. I really want to regulate how much water my plants get. I guess I am, at least, too lazy to measure out amounts of water with glassware each time I water each plant, but come on, that's a waste of time.
Anyways, I've looking into solutions for individual plant pots, and a system for the whole group of plants. (I keep all my plants in one room so my cats don't eat them.) For individual plants, there's that "earthbox" idea where the pot has vents at the base to use the soil as a wick. The entire pot sits in a container of water. When used correctly, this neatly simulates ground water. But I don't want to spend the money on all those new pots. I have considered trying to make earthboxes myself, but I don't have any cheap ideas that I like yet. Maybe if I bought a box of colanders to use as the inner pots. Either way, that idea is out for now. The other local idea I've been considering is using those things called "water spikes" or "aqua spikes." You attach a 2 liter bottle to a spike and push the spike under the soil. You cut a hole in the bottom (now top) of the bottle to add water, and the water seeps out slowly through the holes in the water spike. I like this idea because you can see how much water you have, and you can see how long it takes to dry up. So, if you can guess the rate of evaporation of the water, you can guess the rate your plant takes in water. I'm sure the changing water pressure in the bottle makes a difference as well. Neat. But the only spikes I can find cost more than I'm willing to pay. I wish I could find them at a real store, instead of online where I can't look at them, and I have to pay to have them shipped.
Making a drip system is my final consideration. This one looked pretty cheap, customizable, and it allows me to buy the parts I need at a store I can physically go to, so I'm going for it for now. I've melted a hole in the bottom of a bucket and attached a 1/4 inch hose adaptor through it. The hose runs to inline drippers that are rated at 1/2 gallon per hour. 1/2 gal. per plant per hour is way too much water for me. My system is not pressurized, so I think that slows the rate some. Also, I've blocked the hose adaptor with a wick, and that's slowed the rate to 3/16 gal. per hour. That means that the rate is currently less than half the standard rating. But I need to make it lower. Before I change any more variables, I need to figure something out. The 1/2 gal. per hour rating is with some water pressure. This means that that's just as fast as water is designed to come out of the dripper. In my situation, my wick has lowered the rate that water can flow through the hose enough to reduce the drip rate. I need to determine if this reduced pressure allows for a new constant rate of several drippers in series, or if the lowered pressure is now the limiting factor in the drip rate, causing a new, slower rate for each additional dripper attached and sharing water pressure.
That question determines my next test. I will measure the rate of several drippers in series. If the pressure changes with each inline dripper I add, then I may already have my ideal water flow rate. For example, if I put 24 plants in series at a shared rate of 3/16 gal/hr, each plant would get 3/16 gal per day. If the bucket I'm using holds about 4 gallons, this could water my plants for a week. It may not be all the water some of the plants need, but they will continue to get water over a period of time. That's what I want. Also, that will really help me when I need to go out of town.
We'll see how it goes.