How to Install Winter-Proof Planters
Ask This Old House landscape designer Jenn Nawada installs a front entry planter for a homeowner that will last through the winter
1. Start by insulating the planters with rigid foam insulation. Simply measure from the inside of the planter and then mark it on the foam. A straight edge will ensure the foam is cut perfectly.
2. Once the insulation has been cut, place it in the planters so it lines the outside edges, but not the bottom.
3. Make sure there are holes in the bottom of the planter. Cover those holes with the terracotta pot shards to protect them from being clogged.
4. Line the bottom of the planter with landscape fabric.
5. Fill the planters with potting soil. It helps to put a few handfuls in to ensure the shards and the fabric stay in place before dumping the entire bag in.
6. Plant the boxwoods in the center of the planters. Be sure to tease the roots to keep them from being pot bound.
7. Underplant the boxwood with ivy. It’s okay to pull the ivy plant apart to get smaller pieces.
8. Water everything regularly. This will vary depending on the placement of the planters.
9. Before the first frost, spray the leaves of the boxwood and ivy with anti-desiccant spray to help them preserve their moisture through the winter.
Jenn planted two boxwoods and underplanted them with ivy. Both of these plants and the potting soil to plant them in can be found at home centers. Jenn reused the planters the homeowner already had, but planters similar to that can be found at the home center as well.
To insulate the planter, Jenn cut squares of FOAMULAR 150 rigid foam board insulation, which is manufactured by Owens Corning.
Jenn also used broken shards of old terra cotta pots to allow for more drainage at the bottom of the planter, which can be found at any nursery or home center.
To protect the boxwoods during the winter, Jenn recommends spraying an anti-desiccant spray. The one she referenced in the workshop is Wilt Pruf.