Drip Irrigation

Fresh & Local wrote:We are setting up square foot gardens in Mumbai and we would like to add drip irrigation. The drip irrigation kit you sell indicates that the hoses are 4 inches apart on the main irrigation hose. Two questions:

1. Does this make irrigation completely cover the square foot container and not follow the square feet? Mel says that when watering the plants, you should make a little depression and put a cup of water in the depression. He says you don't need to water the entire garden. How does this square with the complete coverage of the drip irrigation kit?

2. Also, are the hoses punched for dripping directly into the potting mixture or are there smaller emitter tubes coming off the hoses. The hoses I am referring to are the hoses that are 4 inches apart on the main hose.

We are trying to use local products to achieve a good drip irrigation system. It is absolutely essential here as it doesn't rain most of the year. It rains for part of June, all of July and August.

We really like the square foot garden setup and we think it will change gardening in Mumbai.

Final question: Where are there other square foot or square meter gardens in India?

Thank you.

Fresh & Local wrote:Hello,

Thanks for seriously answering our questions. We greatly appreciate the fullness of your answers to help us understand the thinking behind the answers. Some followup thoughts:

1. We are using a vermi-compost and co co soil (made from coconut husks) potting mixture, about half of each. The combination is crumbly, lightweight, and appears to have that great sponge-like quality of holding water but releasing the excess. Is it possible to use pure vermi-compost as the compost or will that be too rich? We are setting up a compost bin (not necessarily vermi) in each of our gardens to make the system complete.

sounds like you have a great mix there. It is very important to have the lighweight mixture because not only is it going to be easier for harvesting and weed removal, but a more friable soil will make it easier to oxygenate the plants and help them grow faster. You can use straight compost if you like, but just be careful of the types of compost that you use as compost tends to be higher in phosphates(salts) and the higher the concentration, the more you might have to water at the start(to wash out the salts) to keep the plants from being stunted in their growth from too much salt. Setting up the compost bin is perfect! that is one of the keys to having great success in your garden. That is black gold!

2. Our drip irrigation system has a main line, sub-main lines (we will use the 4" spacing as you recommend), then micro-tubes into the potting mixture. Does your system use micro-tubes or does it have holes punched into the sub-main lines? How far apart are the holes?

our lies have holes in the drip tape directly(less parts, simpler design) we have the holes 4" apart as well. So 4" between tubes and 4" between holes will give you great overall coverage. Remember, the simpler the design, the easier it will be to make and the more success you will have.

3. Since the square foot gardens are going on balconies and rooftops, we are making full boxes with bottoms. (Mumbai was settled on seven islands originally and though most of the water between the islands has been filled in, land is at a premium. On the other hand, there are millions of balconies and rooftops.) We will put a cloth-like filter sheet in the bottom of each of the boxes. Do you think we should line the box with plastic?

Rooftop gardening is a huge plus. People have no clue how much food you can grow from your garden on a rooftop, it is an insane amount! The great power of this gardening method is it's portability, you can grow them everywhere!. Drip irrigation will be especially useful on a rooftop system as you don't have to worry about getting on the roof to water(out of sight, out of mind in many cases). As for lining the box, some people do it because it will extend the life of their boxes(although in some 3rd world countries where wood is scarce and expensive, people just use rocks to hold the soil together) others do it because they worry about chemical from treated lumber getting into their food. It should be fine if you want to line the boxes, however, just normal wood should last several years before rotting enough to need replacement. the key is to remember to have enough drainage holes. The soil needs to be able to expel excess moisture.

4. The first boxes we will be making are 3 feet by 3 feet. We are using a raised 20 liter bag of water with gravitation to feed the drip irrigation. We plan to install two of the 3 feet by 3 feet. Can we put the two boxes together and run the sub-main lines over both boxes. In this case, we would only have one water source.

The higher the bag of water, the more gravitational assist you are going to get, so the more boxes you plan on connecting to the drip system, the higher you want that bag. I haven't done enough experimentation to see how many boxes can be fed with a suspended bag, so give it a try and let me know how it works!

5. Final question, Mel indicates that his boxes are 6 inches high with 6 inches of potting mixture. We are a little concerned that the potting mixture will run over the top especially in the heavy monsoons. Would you recommend making the boxes a bit deeper, like 9 inches to prevent this from happening.

Actually, I have found that since the soil has so much space embedded in it(because of how friable it is) it will tend to settle. On average, my soil here, when I have put the initial soil right up to the tip of the box, after I water it, settles down about an inch below the tip. You should not have to worry about it. However, if you have any issues, you can always make the boxes higher. We never say that you can't make the boxes higher, just that in most cases, it's not needed. Keep it simple.

6. Where in India are there other square foot gardens? We will be returning for holiday to the United States in June. Is there some place we can go to learn more about square foot gardening?

You can talk to our teacher coordinator for locations of teachers around the world. She can be reached at: belinda@squarefootgardening.com Please keep me up to date on your efforts (please send me pictures of your progress and your boxes, I'll add them to the site! You can send them to: alan@squarefootgardening.com) Also remember that a grid will help keep your focus on the spacing (so you can gain the most density from your garden, so make every box has one)

Thank you so much. We are also serious about ending world hunger.