The fall factor gardening rule tells you to add 1-2 extra weeks to seed packet dates. Your plants grow slower in autumn than in summer. Less sun and cooler temps extend growing time. This fall maturity adjustment keeps you from missing harvest.
I learned about the fall factor the hard way in my garden. Planted spinach 45 days before frost based on the seed packet. First frost came right on schedule. My spinach was half the size I wanted. The plants needed more time in those short fall days.
When I first started fall gardening, I blamed bad seeds. Bought new packets the next year. Same problem. Then a master gardener told me about the fall factor. I added those extra days. My harvests went from tiny to full-sized crops.
Illinois Extension explains why your plants slow down in fall. They use sunlight to make food. Fall days get shorter every week. Your plants get fewer hours to grow each day. Cooler soil also slows root growth. Both factors add up to slower plants.
Your autumn planting timeline needs this extra time built in. A lettuce that matures in 30 days during summer takes 37-44 days in fall. Broccoli that needs 60 days in spring may need 75 days when you plant in August.
Here's how to figure out your actual planting date. Start with your average first frost date. Look it up for your zip code online. Count back the days from your seed packet. Then count back another 7-14 days for the fall factor.
Let me walk you through a real example. Say your first frost hits October 15. You want to grow lettuce that needs 30 days. Count back 30 days from October 15. That puts you at September 15. Now back up 10 more days for fall factor. You need to plant by September 5.
I now add 10 days to every fall planting math I do. Some years the weather stays warm longer. Those extra days give me a safety net. Better to have mature plants early than catch frost with half-grown crops in your garden.
The fall factor catches many new gardeners off guard every year. Don't trust seed packet times for fall planting. Add those extra days to your plans. Your crops will have time to size up before cold weather stops their growth. Your fall harvest depends on getting this math right.
Read the full article: Fall Vegetable Garden: Best Crops to Plant
