I'm a newbie gardener with plenty of experience caring for house plants, but I've never had the chance to start a real garden until now. I'm renting a place with a concrete patio and can't dig into the yard, so I'm thinking about making or buying a raised bed to put on the concrete. My main questions are: Is it okay to place a raised bed directly on concrete, or do I need a different setup since it won't be in the ground? Will the concrete affect how hot it gets? Also, I'm planning to grow tomatoes, which I've read need at least 18 inches deep. Does this requirement mean I need 18 inches of just soil, or can I use materials like twigs or cardboard at the bottom to count towards that depth? Any advice would be super appreciated!
2 Answers
You can definitely use a raised bed on concrete, but keep in mind that you'll have to manage watering and drainage carefully since it’s an impermeable surface. Consider using pots instead if you can; they might be easier to handle and more effective for drainage. If you do go with a raised bed, try to ensure there’s some sort of drainage system in place, like holes at the bottom. As for building materials, look for second-hand wood or even build with fabric grow bags, which are easier to store and move around!
One way to save money is to build with recycled materials or use cheaper supplies for the base. Just remember that it’s crucial to have adequate drainage to prevent standing water, especially on concrete. For growing tomatoes, you’ll want that depth to be all soil—using cardboard or twigs as filler can lead to nutrient issues later on. Good luck, and happy gardening!