I did this for years. I rigged a hose end sprayer with a brass connector, so I could put the ferts in the jar and then let it run.

It didn't burn anything. Later, I started wondering if the fertilizer would eventually clog the pores in the soaker hoses.

I don't think it did, but quit doing it anyway and switched to foliar feeding.

My Automatic Watering and Feeding System
by Henry Kuska, zone 5 northern Ohio

For a number of years (about 10), I have been utilizing an automatic watering and feeding system based on the use of recycled rubber soaker hose, automatic battery operated timers, and water filter cartridge holders. Starting from the garden water faucet, the system consists of the following:

1) An anti-siphon device protected by filters on both the inlet and outlet side. The function of the anti-siphon device is to prevent water from backing up into the house water system if the house water pressure would suddenly drop from something like flushing a toilet. The reason I use filters on both the inlet and outlet side is to prevent particles from entering the anti-siphon check valve chamber. Particle contamination could prevent the valve from completely closing. I replace the anti-siphon devices each season (since mineral buildup could also hinder complete sealing of the valve).

2) The distribution system. After the water leaves the anti-siphon device it is divided into four branches. Each branch has its own battery operated timer and directs the water to a separate set of beds. Each branch also has its own manual on-off valve. I have used both regular PVC plastic pipe and cheap plastic garden hose for the under lawn piping. I used a semicircular edger tool to lift one side of the sod and then I pushed the hose (pipe) under the sod. In the spring the ground is relatively soft and this part of the installation is not as hard as one may think.

3) Battery operated automatic timers. The most important feature to look for is that the unit will automatically shut off when the batteries are weak. Also look for timers with a battery life longer than one season (the first timers that I purchased needed new batteries every couple of weeks). My present timers are good for the season. My timers have a manual on-off feature that does not disturb the automatic settings. I find this feature very useful. Ease of programming is also very desirable (some of my previous timers were not easy to program). I especially like a preview feature that allows me to check and see if the times that I think are entered are actually what are entered. I used to water at night, but I found that "critters of the night" would chew the soaker hoses. I now set the 4 timers to water daily for one hour the first starting at 11 am the next at 1, then at 3 and the last timer to start at 5.

4) Water filter cartridges holders. I use 4 household water filter cartridge holders (one after each timer) to hold whatever chemicals I want to deliver to the rose beds. To save money, I purchased these either at Goodwill type stores or at garage sales. I recommend that you look for units with a clear lower unit and with a pressure release button. I install them backwards to the suggested direction when used as filters. As I install them the water enters from the center of the cover and then exits from the side of the cover. I epoxy a small section of plastic pipe to the center top inlet so that the water goes to the bottom of the cartridge holder (this is not necessary, but it does promote more rapid mixing of the fertilizer and the water). To use a household filter cartridge holder with a garden hose, one should utilize adapters to change from water pipe thread to garden house thread. The adaptors are not expensive, and they are normally available at large hardware stores. The two threads are almost the same; but if you try to force the one on the other , you will cross thread the fitting and probably have slow leakage at the joint.

5) The soaker hoses. Once in the individual bed the water is split into two paths by the use of inexpensive "Y" connectors (with shut off valves in each arm). The soaker hoses are connected at this point. In my most recent beds I use two hoses that run parallel to each other 1/3 and 2/3 of the way from one side of the bed (my beds are about 5 feet wide). In the older beds I snaked the two hoses in and out from bush to bush (the hoses were installed after the bushes were in place so a straight line installation was not possible). I install a manual on-off valve at the termination end of each hose so that I can periodically flush the hose. The first year I buried the soaker hoses. However, the second year I found that the hoses appeared to have lost most of their porosity (presumably due to mineral build up). I now put the hose under the mulch. Each spring I take the hose up and flex it and then flush it. This seems to restore the porosity. Some years I also added enzyme drain cleaner to the water filter cartridges one day before shutting down the system for the season. Sometimes (especially when I am able to purchase them deeply discounted at end-of-year sales), I simply replace the soaker hoses with new ones. I should point out that the water used is untreated well water so the mineral buildup problem may not be typical.

Henry K has it organizationally and I thank him. For the beginner (ME) last year I had a leaky hose end in the corner of the greenhouse where nothing would grow in the past with hand sprinkler watering and I had planted a couple of pole bean seeds which did not sprout in Spring. That leak grew 8' tall beanstalks in a greenhouse I don't use in the summer here on the California desert. So a soaker hose would make a major difference. Next would come a 'drip' type fertilization system on the soaker hoses at low pressure. Couldn't find a set-up on the internet. These soakers WORK and when old and crusty I drill holes (up to 1/16 inch) with my mineralysed water to keep them leaking. Don't backflush fertilizer into your house water!