I'm in San Diego, on the coast. Just installed drip tape on my 6 raised vegetable beds (2 beds- 4' wide/4 rows, 4 beds- 3' wide/3 rows). The tape had emitters every 12". So the installation guide said if there is less than 24" between rows, do one line in between, which suggests these will water 12" on either side of the line. We don't have more than 8"-10" between any two rows, so I've run a line every other row, which according to their instructions is more than enough.

When I ran the system for the first time I noticed that the visible surface wet spots from the emitters were about 12" diameter (so wet along the entire line, and 6" either side). For some lines, the wet spots did not make it to the vegetable row, even though it was well less than 12" to the row. I have 2 questions:

1) Even if the wet spot doesn't make it to the row, will the water spread further below the surface and reach the rows?

2) I only planted my vegetables about 3 weeks ago, so they are all seedlings or still seeds. I understand when they are older their roots will will be spread and deep enough to reach the wetspots. But do I also need to hand water the rows that are not getting the wet spots until they are past seedling age?

Thanks much!

1. Do some probing in the soil and actually see where the water travels and why. Water moves according to the soil structure (fines vs Course grain makeup which creates soil tension). The surface appearance is not an indication of moist soil because of evaporation of the surface water. Run the system longer to see if you get more lateral water movement.

2. You have the right idea about water conservation and root growth. Think of the size of the root ball and getting water just to that part of the plant. Know your plant's needs at different stages of growth. Certain plants like more or less water. You might think about placing the line closer when the plant is young and farther away when the root ball has expanded depending on the plants needs. At the beginning it is all trial and error and how observant you are to your plant's well being. You are smart not to take general instructions literally for all conditions. Gardening is a an art based on scientific principles. You will never stop learning and developing a better way of doing it. JMHO. Aloha

Just add a line.

If you probe down just an inch or two, it is wet and the whole root zone is moist. What will really help is a layer of mulch over the drip tape; this helps the water seep outwards and prevents evaporation. You may also need to hand water the new plants once or twice to establish soil moisture, but the dris should do them OK.

I have a page showing how I use the stuff in a large garden area linked below...