Making the decision between drip or sprinkler irrigation needs consideration. Right off the bat I would say that drip irrigation is the best way for any plant in your bed when the plantings are separate distinct plants. What I mean by separate distinct plants is that they are rowed or you can see individual pants as opposed to plants being so close they blend together, a lawn for example, has individual grass plants but they take a bit of work to see the individual plant and separate it from the rest of the lawn, with plants that close it would not be practical to use drip irrigation.
Drip irrigation is better for several reasons:
- Less water loss to evaporation
- Less opportunity for fungal growth or disease on the plants
- The plants are cleaner
With drip irrigation you put the line right at the base of the plant and the water goes straight into the soil instead of being sprayed out hitting everything. Water on your path doesn’t help, water on the plastic of your green house if it is in a green house doesn’t help, water on your tools doesn’t help. Water in all of these different locations evaporates and gives no benefit to the plants you are intending to water, water is also lost being shot through the air, as all of the water is being shot in droplets through the air some of that is evaporating, there is a lot of surface area on the water droplets for evaporation to take place on. Unfortunately as I stated earlier, for now I am using an oscillating sprinkler, after I am done watering it looks like a sauna in the green house even when it isn’t that warm, all of the airborne water is lost.
When using sprinklers watering is supposed to take place early in the morning, either just before sun is up or right at sun up. The reason for this is so that the water has time to soak in before it evaporates as much (cooler temperatures and no direct sun light), and so that the water on the leaves does evaporate fairly soon (as the sun comes up but still cool). If water is on the leaves in the heat of the day supposedly the water can act as a magnifying glass and actually the light can burn the leaves. If the sprinklers are used in the evening the water sits on the leaves all night creating prime conditions for fungus and/or diseases. The advantage with using a drip irrigation system is that you can ignore all of that and just put water in the soil at the bottom of the plant when you need too.
It’s not a big deal but watering with drip irrigation at the bottom of the plant also keeps soil and compost from splashing up on the leaves, it doesn’t necessarily hurt the plant but it requires more washing to get the leaves clean for processing.
In the past when I have used drip irrigation it was always delivered overhead, hanging from a green house, or laying on benches, in both cases the plants were in pots. I don’t believe that using it in on the ground is much different except when it comes to replanting, if you are going to till, the lines would have to be taken up if they are on the ground and generally drip lines are a pain to deal with. You have one main supply line, probably 3/4 inch, and all these 1/4 inch lines coming off of it, one for each plant. The individual water lines can be stopped up if not needed, most of the lines have a weight on the end to keep them where you put them. Often on the side of the weight is a groove that the line will clip in so if not in use you can bend the line back on itself using the weight as a clip and the kink in the line stops water from coming out. However, getting to the point of drip lines being a pain, if you have a 25 foot line with two drip lines every foot and each drip line is 18 inches you have 50, 18 inch lines getting all tangled together, inevitably some will get pulled out of their holes when you are unrolling the main line, then you need to go back and fix it.
If you are watering using an overhead drip the tangling isn’t a problem but remember you pretty much need a drip line for each plant, you may be able to get away with it for every two plants if they are close but watering may not be as consistent as you wish.
Sprinkler systems are a bit easier to deal with, they don’t care how far apart the plants are or if there are any plants there, they water the same unless you change it. Sprinkler heads can be purchased to deliver different amounts of water so even if you have different plants mixed in a bed (in groups) you can change heads for different locations. There are little sprinklers that would be placed every few feet or big sprinklers like you see at sod farms and golf courses that spray water 30 feet. If you have a high turn over bed you may want to keep the irrigation system outside or on the edge of the bed and permanently out of your way, then you would need bigger sprinklers, if you want to place the sprinklers in the bed you would probably want to use smaller ones. If you want to move them a lot you can make towers for the sprinklers that you connect to hoses and can move around where ever you want, towers have to be heavy however in order to no fall over. Once a guy I was working with got knocked unconscious by a sprinkler when someone tripped on the hose causing the tower to fall over and it hit him in the back of the head, so they can be dangerous too.
There are lots of options, it does take more consideration that what I have just brought to the table but it is a start. Irrigation systems are not necessarily permanent either, being that this is my first year with the green house I will probably buy a sprinkler system first and then see if my planting system would be better served by a drip system. The big decider for me between a sprinkler system and a drip is the number of plants, if there are many plants close a sprinkler may be better. If I buy a sprinkler system and change to a drip there will always be a use for the sprinkler system, it can be moved and used in different beds so it won’t be a waste.
Irrigation can be overwhelming but it shouldn’t be, it just takes time and planning and will probably need adjustments later.