I would line the sides and bottom of the boxes with filterfabric. Depending on what you are putting in the boxes, you may want to consider adding some sort of insulation to protect the roots over winter (if frost is a worry). Your potting soil should do for the first year, but you could add some all around plant fertilizer partway through the year. If you are planting veggies and fruits you should amend the soil with a manure each spring before planting. If you wanted to try and preserve these boxes, you could paint a pressure treating on the inside of the boxes, but make sure it dries well before adding soil and plants. If you are going to add some clear gravel or rocks at the bottom, consider cutting a drain hole at the back of your box to allow water to exit. Best of luck!

Is the hardware cloth that you mentioned to keep gophers or voles out of the beds? If that is your plan, it should go on the bottom under your soil or drainage rock. I've had really good results with a mix of 25% compost / 75% sandy loam.

Thank you! Yes, I have 1/4" hardware cloth but I don't think I have any voles....yet. I plan to grow mostly veggies and some flowers.

About how much drainage rock should I put under the soil? I'll have to buy it by the bag at this point so I'm looking for something cheap. What do you think?

G. Chickened, are you thinking that the soil below will not absorb the water? Usually, raised beds are warmer and drier, so unless the ground below is seriously clay to the point that you would expect it to act as the bottom of a bucket, you might have just as much success lining the bottom thickly with newspapers and calling it a day. The newspaper should suppress seeds for a while then integrate into the soil. If you plant vegetables with strong root systems, they could reach into the native soil at some point. Not an expert, just my opinion.

Thank you. I'm located in Southern California, Long Beach, slightly inland. No frost worry.

Poise, I'm just curious about proper construction. With 1-1/2" deep bed, I simply want to construct properly and preserve the redwood as long as possible. I have the weed barrier and 1/4" hardware cloth now. If I don't need gravel, I won't bother. We get warm days in So Cal so I imagine the beds will heat up and moisture will evaporate. I can drill drainage holes along the lower panels if advised? We are having some 100* now in So Cal in late March!

We build in Northern California and typically line the bottom of the open box with 1/4 welded hardware cloth , stapled to the interior sidewalls about 6 inches up the sides.

We do not line the interior sidewalls with anything or coat them with any sealers. The redwood starts to rot out at year 12 to 15.

We use an organic OMRI approved vegetable back fill mix for the beds and break up the soil below the bed and work in the veggie mix about a foot deep before installing the welded hardware cloth or the automatic drip system.

We have removed several raised beds over the years that were lined with weed barrier cloth and gravel. The soil had become anaerobic. I would suggest no drain rock or lining so that you retain a free draining + breathing box.

Dear Chickadee,

My leaning is towards "natural" when it comes to my vegetables. I use soaker hoses which are a plastic material so I guess that could leach something that could get into my food, but overall I try. After all, part of the point (IMO) of gardening is getting fresher, healthier vegetables. That is why I would steer you away from sealants and plastic sheeting.

For drainage, I would expect the water to absorb into the ground beneath. Also, unless you built that thing water tight, the gaps between the boards should help the soil to breathe. Give it a try and then take your electric drill out for a hole or two if you continue to be concerned.

They look like great boxes and your area is great to grow in. Less pests, great weather. I believe you will enjoy using the boxes!

Thank you, Posie. I don't intend to use plastic at all. I have weed barrier fabric which is breathable.

Often those fabrics are made of petroleum derived fibers (more accurate?). Maybe you are using burlap (natural fiber?)

I would not line with weed fabric, particularly the bottom of the bed. It will prevent roots from extending into the native soil, will hinder the movement of air and water (as per Michele Derviss's comments) and will also prevent soil biota from migrating into your beds for healthy soil. At a previous home I had raised redwood beds similar to yours used for a large veggie garden. The wood sat at ground level and were anchored by 4"x4" posts. We loosened soil below the level of the beds for several inches, and mixed a combination of native soil, plant compost, and composted cow manure to fill the beds, with the majority being native soil. The beds produced very well and were virtually weed-free when mulched with chopped leaves, and when we moved after about 10 years, the beds were still holding up well. We did mulch the paths between the beds so that we didn't have to worry about grass and weeds invading the beds.

Voila! Now I have dirt!

I've just posted a new discussion which might be of interest to some people following this discussion.

Want to know about correct soil amendments for your new raised garden beds? Find out more here.

http://forums.gardenweb.com/discussions/3050055/m=23/raised-garden-bed-4-x-8-soil-amendments-recipe