For thriving carrots in your urban garden, the depth of your planter boxes is crucial. Carrots require deep, loose soil for their roots to develop properly. Generally, a minimum depth of 12 inches (30 cm) is recommended. However, for longer carrot varieties, opt for planters that are 16 to 18 inches (40-45 cm) deep.
The key is ensuring the soil is light, well-draining, and free of stones or compacted clumps to prevent stunted or forked roots. Choose shorter carrot varieties like 'Parisian' or 'Little Finger' if your planter is on the shallower side. Always check the seed packet for the specific variety's mature root length and choose a container that exceeds that depth by a few inches. This allows ample room for the taproot to grow straight down without obstruction, leading to a sweeter and more robust harvest from your city oasis.