Timing is everything in gardening, especially in urban spaces. For most climates, the absolute best times to set up your new urban planter boxes are early spring and early fall.
Spring is the classic planting season. As the frost recedes and daylight increases, it's the perfect moment to sow seeds or transplant seedlings for a bounty of summer vegetables like tomatoes, peppers, and herbs. The warming soil encourages strong root growth. In early fall, as intense summer heat fades, you can set up planters for a second harvest. Cool-season crops like lettuce, kale, and radishes thrive in the milder temperatures.
Consider your local climate above all. The general rule is to plant after the last spring frost and about 6-8 weeks before the first fall frost. For a head start, you can assemble your boxes and fill them with soil a week or two prior to planting. This allows the soil to settle. Whether you choose spring or fall, ensuring your planters receive adequate sunlight and water will set your urban garden on the path to a flourishing season.