Don't Wait: Try This Money-Saving Cardboard Hack In Your Garden Before Winter Hits

While not all plants are susceptible to the freezes that can occur before winter dormancy, there are many that wither during an overnight chill. When the water inside a plant's cells freezes, ice crystals form and burst through the cell walls, leading to withering and potential death. As such, if you fail to protect your more cold-sensitive plants from freezing temperatures, intense damage can occur. Luckily for you, cardboard is to the rescue. 

If you want the benefits of horticultural wool for freeze protection but don't have any at your disposal, or are just looking to save some cash, cardboard is a great option. Instead of tossing your delivery boxes, place them right over your vulnerable plants like a mini shelter to lock out the cold. Made from layers of paper pulp — a natural byproduct of lumber processing — corrugated cardboard is sturdy enough to withstand moisture and wind while still breaking down naturally over time.

Unlike plastic garbage bags, which should never be used to cover your plants, cardboard does not trap moisture or draft in cold. Instead, the corrugated layers allow the interior air to circulate, as well as provide the necessary insulation from the cold air outside. Placing a cardboard box over your cold-sensitive plants will trap the natural heat that the plant and soil create, which protects the plants from severe changes in temperature, such as overnight flash freezes.

That said, you will want to size your boxes to your plants. The technique won't work unless you can cover the entirety of the plant while also not being too tight, as this could suffocate the plant. This method will work equally well for potted plants and those in garden beds. It's also important to remove the cardboard once the chance of frost has passed, as leaving it on too long can waterlog the cardboard, creating a haven for potential pests and diminishing its insulating qualities. You can also flatten the boxes and layer them around the base of plants for extra insulation — and as a bonus, the cardboard will naturally break down and enrich the soil over time.