If you’re wondering why your plants sometimes aren’t doing very well and you’ve done everything possible, the problem may be they need more root space. Whether growing in raised beds, or in the ground, it’s important to consider how much space they need beneath.
I always try to give them more root space than needed.
The following guide should give you a starting point. However, keep in mind just because a plant is shallow-rooted, it may need much more lateral space to grow outwards.
Very Shallow-rooted (can grow in 6-8″ soil)
Shallow-rooted (can grow in 12″ soil)
Blueberries (wide roots)
Herbs (most, like basil, cilantro, mint, oregano, parley, thyme)
Medium-rooted (can grow in 16″ soil)
Deep Rooted (requires at least 24″ soil)