Having a greenhouse with out year round water is a trick, especially when watering new plants in the greenhouse. Anybody knows that almost all plants need regular water, even if it is only once a week. In the summer we leave a heavy duty hose laid out for watering and we can drag it to where ever we need but because we garden in zone 4 we had to figure out a way to bring the water to the greenhouse in the winter and spring. A hose would freeze in a short time if left out in the cold. As a matter of fact we have had occasions when the temperatures are below zero where the hose would freeze up while we were using it. It is a lot of trouble to bring 150 feet of heavy hose inside to thaw so we try to fill the watering barrels when the temperature is above zero.
The greenhouse is about 100 feet from the studio and anther 50 feet to the source of water in the basement of the house. We would have buried a line to the greenhouse but there is a sewer line that runs between the studio and greenhouse but no one is really sure where it is. In the future we will probably figure out where it is but for now we stick with our water barrels.
We bought a few 55 gallon plastic barrels that were used for importing fruit concentrate to the United States from France. The barrels are blue in color and have open tops. We put the barrels in the front part of the greenhouse directly in front of the intake louvers. This way they divert the incoming air so that the plants do not get blasted with cold air when the exhaust fan activated on those sunny January and February days.
We made a top out of a piece of Advantec flooring and it is used to cover the barrel that is not being used. The cover works as a shelf to hold the watering cans and it is waterproof. We made the cover for the water barrels by starting with a square of 3/4 inch material that was about 6 inches wider than the top of the barrel. Then we cut the corners off equally to end up with a stop sign shape. Octagon for math and geometry heads. Then we rounded all the edges with a router and a 1/4 round bit.
It is easy to slide the cover from one barrel to the next. Another good thing about leaving the water in the barrels is the fact that the chlorine will dissipate. We are on city water and they use chlorine and who knows what else. The present water source is fine other wise but in the past we had really hard water. It spotted all the pots and trays with white residue.
The house water went though a water softener so we had to make a separate hookup for plant water that did not go through the softener. The problem is the softener cleanses it self with salt and a residual amount of salt remains on the resin after cleaning. It is debatable how much salt is passed into the water system but we did not want to take a chance. Salt is not good for the plants we grow in the greenhouse !
Once the barrels are full we can dip the water our using the watering cans. The spouts make perfect handles and it is easy to reach even the last bit of water. We have several sizes of watering cans and they will deliver everything from a gentle shower for seedlings to a fast stream that fills baskets quick. 2 gallons of water is fairly heavy when reaching for hanging baskets so we want to be able to finish the job in a hurry.
The barrels work good in the winter and early spring because the plants watering needs are lower than in the spring. For example we have geraniums that only get some water every 2 weeks in the winter.
The spring is a different story because all the benches are covered with flats of growing plants. The plants probably use 1/4 of the water and the rest is lost to evaporation. On a sunny day the temperature is high and the sun warms the dark potting mix. In the evening when the temperature goes down you can see steam rising from the flats. Not to mention the water used to wet the ProMix when potting.
ProMix comes in large compressed bails and it is bone dry when we get it. It has to be wetted before using because a dry pot of it would shrink to a half a pot when watered. We mix it in a yellow pail for starting flats and a wheel barrow for larger hanging baskets and pots. We use the yellow pail so that we can be sure the pail has not been used to hold old dirt, dried up leaves and other things that might introduce bad mold and fungus to the starts.
So we go through more water this time of year but now that the temperatures are getting higher we will be able to leave the hose out all the time. The hose and wand allow us to reach all parts of the benches easily and make sure we can deliver enough water to keep the plants happy.