Absolutely! Adding a small trellis to your existing urban planter boxes is not only possible but a fantastic idea for growing peas. Peas are natural climbers and will thrive with vertical support, which maximizes your limited space and improves air circulation to reduce disease.
The process is straightforward. First, ensure your planter box is sturdy and has enough soil depth (at least 12 inches). Then, choose your trellis material. Simple and effective options include bamboo stakes tied together at the top, a piece of coated wire mesh or garden netting attached to wooden stakes, or even a repurposed small ladder section. Secure the trellis firmly into the soil at the back or center of the planter, leaning it slightly inward for stability. Avoid making it too tall or heavy for the box to support, especially in wind.
Once installed, gently guide the young pea tendrils onto the trellis. They will quickly take hold. This vertical approach saves ground space for other plants, makes harvesting easier, and keeps the pea pods clean and healthy. So, go ahead and give your urban peas the support they need for a bountiful harvest right on your balcony or patio.