By Sally McCabe, PHS Associate Director of Community Education 

To maximize growth in October, a bit of planning is necessary to ensure you can harvest crops before the cool weather swoops in. Below is an overview of some key things to tackle in the garden this month to ensure a fruitful harvest through the fall and lay the groundwork for a vibrant garden in the spring. From managing frost-sensitive crops to planting cover crops and bulbs, here’s everything you need to keep your garden thriving! 

Frosty Temperatures 

In the Philadelphia area, the first frost can be expected anywhere between October 15 and October 31. But there are many types of frost! There’s the just-too-cold-for-the-basil frost (around 40°F); the nipping frost, which nicks the tops of tomatoes and the edges of annuals; the really-heavy-dew-on-the-low-spots-on-the-lawn frost, which kills most of the annuals and any tomatoes you haven’t covered at night with a blanket; and the white-stuff-on-the-windows frost, which makes all the leaves fall off the ginkgo trees in one day and leaves frost on your fall pumpkins.  

After this comes the killing frost, which dips below 28°F and wipes out all the plants you’ve been trying to protect in the garden. Beyond that is the H**-freezes-over* frost, where the ground freezes solid, hoses, rain barrels, and water pipes burst, figs are lost, and even spinach dies!

Pay Attention to Weather Forecasts 

Just in case the weather ever becomes predictable again, we’re due for frost around Halloween. Be ready to cover tomatoes and peppers with blankets or plastic if it drops below 35°F. Last year, I did this and managed to keep the plants alive long enough to have tomatoes into December. If frost prevails, clear out the dead vegetable plants and throw down some last-minute cover crop seeds—hairy vetch and winter rye are about the only ones you can plant this late. Otherwise, cover the empty beds with mulch or shredded leaves. 

Rip Out Tomatoes 

Now that the heat has broken and we’ve had a little rain, the tomato plants are vibrant green and full of yellow flowers. Unfortunately, frost is less than a month away, so those flowers are just for show. Unless the plants are loaded with good-sized fruit, it’s time to cut your losses. Yanking the plants out by the roots and hanging them up will force much of the fruit to ripen. Any that don’t ripen by the first frost warning should be brought inside to ripen on your windowsill. 

Plant Cover Crops 

Use that tomato-vacant space to plant your last crop of greens: spinach, lettuce mixes, arugula, mustard greens, and mesclun mixes. Planted now, they should grow enough for a Thanksgiving salad, often lasting into the December holidays and beyond. These cool-season crops will germinate quickly thanks to increased soil moisture and cooler air temperatures. Simply broadcast the seeds lightly and cover them with a quarter to half an inch of soil. Water lightly and let the fall rains do the rest. 

Move Houseplants Inside 

Now is the time to start transitioning houseplants indoors gradually, before the heat comes on. First, get them accustomed to the lower light levels indoors, then let them adjust to the lower humidity. Remove any dead or damaged leaves and check for pests; if possible, pull each plant out of its pot to ensure you’re not bringing in unwelcome guests. Do this now, not at the last minute when the frost alarm sounds! Trust me—I have advanced degrees in procrastination! Bringing all your houseplants inside on the same night guarantees praying mantises in the bedroom, katydids in the curtains, loud chewing noises at night, and snakes at the breakfast table. Not to mention the chiropractor bills the next day!

Plant Bulbs 

October is also the perfect time to plant bulbs! A simple rule for bulbs is to plant them point-side up, at a depth three times their height. So, if a daffodil bulb is 2 inches tall, plant it in a 6-inch hole. Planting them deep enough keeps bulbs from being pushed out of the ground. Add a tablespoon of bulb fertilizer to the hole and cover the area with an inch or so of mulch for insulation. To avoid the temptation to plant them symmetrically, toss handfuls of bulbs onto your beds and plant them where they land. Don’t forget to mix different types of bulbs to add diversity in color and bloom time. 

Put Your Amaryllis in the Basement 

Are you an amaryllis owner? If so, it’s time to bring them inside too! I brought mine in from plant camp this week, and the leaves are huge and beautiful. They need at least 6-8 weeks of dormancy, so I put them in the basement in total deprivation mode—no water, no light—until all the leaves die back. I’ll revive them on a sunny windowsill in January, just in time to bloom as the new store-bought ones start to fade. 

Harvest Potatoes 

By now, potato plants should have died back, but even if they haven’t, it’s time to get those babies out of the ground before they resprout. Use a spading fork instead of a shovel to avoid cutting your spuds in half. 

Looking Back 

Aside from these tips and tricks for October gardening, now is a great time to make a list of what worked this year and what didn’t. Consider what elements of your garden need to be changed or corrected come spring—and write it down now before you forget!