retire:

This sounds like something one might try in this area where the native soil is pH 7.5. Don't know why you would try it unless your pH is high also.

As to the actual setup, 14 inches or less to the water table sounds a little shallow to me. I'd make the trench deeper. I'm also wondering how much settling you will get. If your compost settles 2 inches the surface will only be a foot above the water table.

Also, waiting until you plant to adjust pH may not be the best plan. If the compost is pH 6.5 or lower you will probably be OK.

Where is the water coming from? If from a well, the pH could be too high causing continuous problems.

So why not plant in the ground? Rain and natural soil will take care of most of the potential problems I've covered unless your soil is high pH or very poor drainage.

The problem I am seeing is that your trench won't drain, so unless it is inside a greenhouse, your plants will drown when it rains.

You can grow blueberries in containers, so I don't see a huge problem with the actual planting space. It does seem like a lot of extra trouble, though, unless your soil is just too alkali to support blueberries and too alkali to have the pH lowered.

Why are you going through all this. It looks like you live in Maryland I do. Our soil is sandy and alkaline. Adding Sulfur is a good idea. I just planted my Duke, Bluecrop and Bonus Blueberry in the garden soil and added sulfur. We are having very good crops. The only thing I want to plant Elliot to give us sime late season production.

Ditto - just dig hole / fill with organic matter and sulphur / check pH / plant. I only need to water my blueberries when it gets really dry, which means most years I don't water them at all. So I don't see why you need the fancy irrigation system.

I would dig wider than 20 inches, blueberries are very shallow-rooted but the roots will spread out a lot more than that. The baby plants I got from the nursery already had roots 20 inches wide. If you want to save on overall digging, make it less deep to compensate.

Scott

I will respond to your comments and suggestions in an attempt to get more suggestions. Yes, I live in Maryland. However, my soil is not sandy. Based on information about blueberries I think my best option is to make a trench and remove the soil and fill it with aged horse manure/sawdust mixture. Placing 6 mil black plastic in the trench with a bulk head fitting with a pipe attached to run into a catch barrel would keep the soil moist but would allow standing water to drain away. Also, during the hot summer the surrounding area would not wick the moisture away from the plants. Having the catch barrel I can recycle the water into my rain barrel. The irrigation system would not be fancy just drip line hose from the rain barrel to the plants. This would allow me to go on vacation and not have to worry that by plants will die from lack of moisture. Since I will have the trench dug the extra cost for the plastic and drip irrigation line would be minimal with a greater return in convenience and the health of the plants. With the added information does anyone have any more suggestions or opinions they would like to share. Thanks in advance for all your input.

Let us know how it works for you.

Retire2,

Answers to some of the questions presented above would sure help everyone better understand your project and might lead to better suggestions.

As fruitnut and scottfsmith asked, why such a small trench/rootzone? The root system of most mature blueberries certainly dwarfs the dimensions you gave for your trench. With such a shallow soil profile, don't you anticipate a serious drainage/moisture problem? How did you happen to decide on the dimensions you gave?

As oregonwoodsmoke asked, have you considered the problems associated with the trench not draining (especially possible soil saturation during and following rain)?

And, as everyone seemed to ask, why go to all this trouble (especially with all the possible complications)? Maybe you have something in mind that the rest of us aren't considering, but it sure seems like an overly complex/potentially-problematic way to go about growing blueberries to me.

Thanks for the input. The dimensions (which could easily be changed) was based on the following college horticultural recomendations for width and depth in inches: Ohio State 18x18, NC 18-24x6-8, Iowa 24-36x12-18, Missouri 36-48x8-10, CA 36-48x12, Washington State 14-18 deep. In addition Cornell University, Washington State, and Missouri recommended drain tiles for soil that was slow draining. In addition the recommendation for containers was to plant in a half whiskey barrel (which appears to be 24 inches in diameter and 18 inches tall. The reason for the bulkhead fitting is to run a perforated drainage pipe 2 inches off the bottom of the trench into a collection tank. I would think that this would eliminate any chance of drowning my plants because the excess water would be drained away from the root zone. Much of the information I have read says to have a high organic matter content. Composted horse manure and sawdust would seem to be an ideal mix. The water source would be rain water. I have a well but would rather not use it. Thus the reason for trying to recycle the water and to eliminate any way for the water to escape to the surrounding area. That is the reason for the plastic. Please continue to post your opinions and questions and I will try to explain my thought process. This is a planning stage and I am trying to get it right the first time. My goal is for healthy plants, water conservation, minimal labor input after the initial planting.

I agree that you will not be happy with the plastic, as it will limit growth as your plants mature and could potentially cause root rot issues.
10+ years ago I simply rotovated a few bales of peat moss into my soil and planted 5 bushes. Every year or so I get a truck load of fresh sawdust from our local mill and topdress the area, as the roots don't like competition from weeds. Haven't added sulphur or fertilizer yet.
I also have soaker hoses running the length on each side of the plants and after many additions of sawdust, the hoses are buried in there somewhere. We get into the hundreds in the summer, but watering is no big deal as the sawdust keeps the moisture in well.
Good luck with whatever you decide.
Flora

Retire2, I also live in Maryland and my soil is also not sandy and I did not worry about drainage. Unless you have rock-hard clay or a low site you should not have a problem. It sounds like you want to put in the irrigation system so go for it; just be advised it will hardy ever be needed though. Re: the bed size, I think their idea is the young plants will only need that wide but then in later years you will be putting down mulch and acidifer in a wider radius (I looked at the Ohio State site for example and they mentioned putting sawdust 4' around the bush). I would say its better to do a bigger area initially, especially if your soil is not very good -- in a few years your roots will be in that not so good soil. In other words I think Missouri is thinking smarter than Ohio here :-)

Scott