Garden Boxes on Patio

I am building vinyl planter boxes on our tile patio. 7ft long, 3ft wide  and 22 inches deep. Does Mel's mix work with a container this deep?  I was told to construct the planters this deep to protect the plant roots from the heat of the tile patio.

JmomCal, Welcome to the Forum from Fresno, the land of HOT summers. Have you been able to read the book All New Square Foot Gardening? You will find out that you don't need to build the beds that deep for gardening. You mentioned vinyl for building the boxes. Is this for looks?

This is what I'm thinking. No, you don't need a bed 22" deep. Trust us. I just went outside and measured cedar boards used for fencing and the vinyl siding (wood grain pattern) used for our house facade. The cedar boards are 7 1/2" wide and the siding is 8" wide. You could build the box of cedar fencing and wrap with the siding for looks and extra insulation. Paint the siding any light color to reflect the summer sun. Set the frame on the patio and line the inside with construction grade weed fabric, bringing it up a couple inches or more up the sides, but not showing when filled. Fill With Mel's Mix up to 6-7', leaving 1-2" for mulch. Mulch is the secret for surviving summer evaporation and keeping the Mel's Mix cool. One more question - can you walk all the way around the box? If you can't access the back side, keep the box to 2" wide so you can tend to the back plants.

Please feel free to ask questions. Also, the Search box has a wealth of information and there are a gillion photos throughout the threads.

Thank you for the information. I order Mel's book on Amazon and it is supposed to arrive today. How thick are the cedar boards you used? Did you use 1 x 8 lumber or the actual cedar fence slats? Also, I've been told that tomatoes need 12 inches root space so how can tomatoes grow in a 6 inch box?

That's great that you ordered the book.  I read it in 2 days so it's an easy but informative book.  How can tomatoes grow in 6" of Mel's Mix?  Well, it's the Mix!!  Plants need something to anchor their roots, water and food (and sunshine).  The 6" of MM provides anchorage and food, and helps hold water.  Here are corn and beans growing in 6" of mix.  You can see a tomato growing in the background box.

I don't use cedar pickets anymore, only 2" x 4" studs.  Wood is a wonderful insulator against heat and freeze, so the thicker the better.  This bed is made of 3 layers of 2" x 4" for a finished height of 10.5".  I filled it to the top of the second row or 7".  Plenty of room to top with chopped hay as mulch.  

This is a small 1' x 3' bed made of 8" x 3/4" (finished 7 1/2" x 1/2") cedar picket.  I have 5 of them scattered in small spots but they dry out faster than the ones made of 2" x 4".


PS: My husband is the one who builds the beds for me. Also, some of the beds are made with free scrap studs from construction sites. Got permission from the site supervisors first.

jmomcal, you need to get your hands on a copy of All New Square Foot Gardening 2nd Ed., by Mel Bartholomew. Soooo many people, and very knowledgeable folks will say "it can't be done' in 6 inches of MM, but it can! And with amazing results, I might add!

It is being done by every person on this site! Hope to see lots of pictures!

from Ohio!