Installing a greenhouse means you can start seeds in February while the ground outside is still frozen. Once it is built, you gain a climate-controlled space that keeps your plants alive through unpredictable spring frosts.
Buy your kit in late winter. Shops are often clearing out old inventory before the spring rush, and you are more likely to catch a discount when demand is low. Expect to spend about $900 for a decent starter kit.
Remember that the 0% intro APR is just a temporary window. If you still have a balance after the 15 months end, the bank will start charging you regular interest on what you owe.