plant box drainage- gravel,no gravel?

[gs]

Hi-

I just built a 2 ft high plant box in my backyard where I plan on growing veggies. I built it on the dirt and did not think about the fact that my back yard is made up of clay like soil. I have read mixed messages on putting gravel/sand at the bottom to avoid drainage issues. Does anybody have any insight on this. Has anybody used it and had success? Do you think I even need to worry about drainage issues since I will have about 1.5 ft of good soil to work with, and it is on soil (even though it's clay like)? If you all think I should put in gravel, how deep does it have to be to work? I would love any feedback.

[rainbowgardener]

No gravel needed if you are building them on top of your soil. Even though it is clay, water will drain down into it. You want the earthworms and other critters to be able to migrate up into your box.

[applestar]

It helps if you fracture the soil underneath with a gardening fork -- plunge the tines in and step on it, then wiggle the top to create fissures. Pull straight out. Creates air pockets and seepage paths for the water and microbes to get in and start their work. Earthworms will use them to get around.

In fact, if you have a sloped area, like I do, the water will shed along the top of the clay soil and provide excellent drainage.

[gixxerific]

I agree with Rainbow, especially if you are adding good soil to the box. The soil you add should have good drainage. Not to mention it will be roughly 2 foot of better soil before it hits the clay like substructure.

[applestar]

Right. I wouldn't add gravel because that would interfere with the ability of the plants ( and the soil biology ) to grow into, and make use of, the clay subsoil.
Make sure to add good compost.

If you haven't added soil to your "box" yet (I couldn't quite tell from your post. We call them "raised bed" around here, BTW.), lay 4 layers of black ink newspaper (or unprinted newsprint and kraft paper -- that's what I use -- often used as packing material) on the bottom if you had weeds growing there before, wet it down, then composted manure, then good compost/soil mix. If you're using uncomposted manure, then that should go UNDER the paper. (You can actually do this directly on top of existing lawn or vegetation without digging or tilling. I use corrugated cardboard if I'm prepping a new bed in autumn to be planted in spring, but for spring prep, it's safer to use thinner paper so as not to block the growing roots.)

[gs]

thank you all so much! this is my first time doing this and I am so excited! I really appreciate your advice (and fyi and the fact that it is called raised bed- not plant box). it's nice to know you all are out there looking out for each other.