I'm in the process of planting my garden, and I had planned 3 ft wide raised beds with a single soaker hose running down the center of each one. I am using a square foot layout, so there will be 3 rows across most of the beds. Will this hose layout be enough to reach plants that are in the outside 2 rows? Or do I need to run 2 hoses between the rows, so they're 18" apart? I'm not sure if soil composition or density will greatly affect the moisture distribution or not. Is this just something I'm going to have to experiment with to determine?
After a week of observation and some supplemental watering with a regular spray nozzle, I ended up buying more hose and running two down each bed between the rows. The water wasn't reaching the outermost edges of the beds with only one hose. When I water now, the entire bed is moist.
Side note: It turns out that a regular spigot has problems with supplying enough water for 8 soaker hoses totalling 500' running in parallel. I have a splitter setup that allows me to run half the garden at once, then I can switch to the other half.
Also, since my yard was slightly sloped away from the spigot, I couldn't even run 2 hoses in series. I wanted to try a 75' hose + a 50' hose in series wrapping back towards the top of the garden for each bed. The second hose wouldn't weep the last 25' though, so I had to buy another 4 way hose splitter and feed everything from the top end.