How much topsoil is needed on top of gravel?

[Natearsenault123]

So I made a garden with 18 inches of good soil and right below that is gravel. Am I ok...or should I put more then just 18 inches

 

[Farmer88]

So I made a garden with 18 inches of good soil and right below that is gravel. Am I ok...or should I put more then just 18 inches

When you say gravel, do you mean the box is built on a driveway? 18 inches should be adequate, however if the drainage below the gravel is unsatisfactory, go up to 36 inches to deal with any poor drainage allowing roots to stay above the oversaturated zone and the soil should whick the moisture from the bottom sort of like an Earthbox. Not an ideal situation with standing water close to the root zone.

Can you provide any more information about your garden plot.

 

[Natearsenault123]

When you say gravel, do you mean the box is built on a driveway? 18 inches should be adequate, however if the drainage below the gravel is unsatisfactory, go up to 36 inches to deal with any poor drainage allowing roots to stay above the oversaturated zone and the soil should whick the moisture from the bottom sort of like an Earthbox. Not an ideal situation with standing water close to the root zone.

Can you provide any more information about your garden plot.

Ty so much for the response...I'm new to growing! It's not in a driveway...lol but imo it might as well be. I built a 6 by 10 gardenbox behind my house (nice green grass) n put manure then promix. Lots of it! As I transfered the clones to garden yesterday is when I noticed the rocky gravel! I'll post some pics

 

[Farmer88]

Ty so much for the response...I'm new to growing! It's not in a driveway...lol but imo it might as well be. I built a 6 by 10 gardenbox behind my house (nice green grass) n put manure then promix. Lots of it! As I transfered the clones to garden yesterday is when I noticed the rocky gravel! I'll post some pics

I think you can get away with it. Its not like on top of a parking lot, just some crappy dirt. When you have completed your season cover the garden with a heavy tarp and seal in as much heat as you can. As soon as the soil warms a bit, around March depending on your location, plant a quick mustard green cover crop and allow it to go achieve flower but not going to seed. This will help break-up lower soils over time. You can also use sunflowers but it will interfere with your cash crop season.