I Never Pull Up My Tomato Plants After Harvest Without Doing These 7 Things First
Spent tomato vines may look like a cleanup chore, but they can still provide seeds for next year, valuable compost material, and a head start on spring.
By mid-October, many tomato plants look pretty rough, with yellowing leaves, a few stubborn green fruits, and stems flopping over their cages. The easy move is to yank the whole mess out and drag it to the trash or the compost pile. Before you do, though, there’s some useful work hiding in those tired plants.
Good end-of-season tomato plant care starts with a close look at what you’re pulling. Some vines can feed next year’s garden as compost, and the best fruit can give you free seed. Others may carry diseases you don’t want to spread around the yard or carry over into next summer.
That’s the main thing to keep in mind as you work. Healthy tomato plants can usually go in the compost, while diseased ones should be bagged and disposed of according to your local guidance. Nearly every other job, from saving seeds to cleaning cages, depends on knowing which kind of plants you have.
1. Check Plants Carefully for Disease
Walk the row slowly and look at leaves, stems, and fruit before a single plant comes out. A few problems should never go into a typical home compost pile. Late blight (Phytophthora infestans) is one, and the bacterial tomato diseases are others, including bacterial spot (Xanthomonas spp.) and bacterial canker (Clavibacter michiganensis), which can survive in plant debris. Mosaic viruses are worse still – tobacco and tomato mosaic viruses can hang on in dried plant debris for years. Most backyard piles never get hot enough, evenly enough, to kill these organisms. Bag those plants and get rid of them according to your local rules, and do the same with any plant that’s heavily infested with pests.
2. Save Seeds from Your Best Tomatoes
Seed saving only works with open-pollinated or heirloom varieties – hybrids won’t come true to type, so an F1 tomato’s seeds can give you something quite different next year. Pick fully ripe fruit from your healthiest, best-tasting plants and scoop the seeds and gel into a glass jar with a little water. Stir it twice a day for up to about five days, until it ferments and the good seeds sink. Pour off the floaters, rinse what’s left in something like the Farberware fine mesh strainers from Walmart, and dry the seeds on a coffee filter or paper plate.
Once a fingernail can’t dent them, they’re ready for labeled paper envelopes; the Lotmer seed-saving envelopes from Amazon are printed with seed name, variety, date collected, and growing notes. Kept cool, dry, and dark, tomato seed usually stays good for about four years.
3. Take Healthy Cuttings Before Frost
This one’s optional, but if there’s a variety you loved this year, you can carry it through the winter indoors. Pick a few healthy side shoots about 3–4 inches (8–10 cm) long and snip them off with clean pruners – Fiskars' bypass pruning shears, available on Amazon, are a great budget-friendly pick if you need a new pair.
Cuttings will usually root in a plain jar of water, as long as the cut ends sit 1–2 inches (2.5–5 cm) under the surface and the jar stays somewhere cool and bright. Once roots show up, pot them and give them all the light you can. Don’t put this off until after a hard frost has already hit the garden.
Leave out any plant that had disease problems, and viruses in particular, since a cutting can carry them along from the parent.
4. Compost Healthy Plants the Right Way
Healthy vines are worth composting, but toss them on the pile whole, and they’ll take ages to rot. Chop them into short lengths first – 8–12 inches (20–30cm) or so – because smaller pieces break down faster. It also pays to strip off any leftover tomatoes. Seeds can make it through a backyard pile in one piece, and you may find volunteers popping up next summer.
Layer the chopped vines with dry leaves or other brown material. A compost bin like the Redmon 65-gallon compost bin from Walmart keeps it all corralled.
If you’re on the fence about whether a plant was healthy, use that compost away from where tomatoes will grow. Healthy potting mix from containers can go on the pile, too, so dump those pots before you stack them for winter.
5. Remove the Roots (or Leave Them?)
For plants that stayed healthy all season, there’s a good case for leaving the roots in the ground. Just cut the stems off at the soil line, and the roots will break down in place, adding organic matter without much soil disturbance. A plant that wilted, stunted, or yellowed for no clear reason is another story. Loosen the root ball with a spading fork, like Home Depot’s Ames 4-tine forged spading fork. You’re looking for knotty swellings on the roots, a sign of root-knot nematodes (Meloidogyne spp.).
Remove infested roots soon after harvest and leave them out of the garden. The same goes for plants with Fusarium wilt (Fusarium oxysporum f. sp. lycopersici), which can persist in soil for many years. In containers, tip the root ball out and check it the same way.
6. Clean and Disinfect Cages, Stakes and Supports
Some disease organisms ride along on tomato supports. Bacterial canker can persist on stakes, and mosaic viruses can last weeks to months on stakes and trellises. Knock off the dirt first, then scrub or hose them down, since soil blocks disinfectants. Then soak them fully in a 10% bleach solution (1 part bleach to 9 parts water) for at least 20 minutes.
Rather skip the bleach? ZeroTol 2.0, an OMRI-listed hydrogen peroxide product sold on Amazon, is labeled for hard, nonporous surfaces like metal cages and tools. Wooden stakes are trickier – bacteria can hide in the wood – so toss any that held canker-infected plants. Plastic pots can get the same bleach soak, followed by a good rinse.
7. Recharge the Bed for Next Year
Bare soil over winter is a missed opportunity. Winter rye is very cold-tolerant and grows in cool weather. In mid-October, it’s still an option in many areas, as long as you sow it at least four weeks before steady cold sets in. You’ll find Mountain Valley Seed winter rye on Amazon in a 5-pound bag on Amazon. Mow it in spring before it sets seed, then turn it under two to four weeks before planting.
If it’s too late for a cover crop, spread compost such as Back to the Roots organic compost, available from Home Depot, or a blanket of shredded leaves, instead. Next year’s tomatoes should go somewhere else, too – keep tomatoes, peppers, eggplant, and potatoes out of that spot for three to four years. For containers, reuse potting mix only if the plants stayed healthy, and replace the top 6 inches (15 cm) in big pots with fresh mix.
Your Post-Harvest Tomato Checklist
Once the last tomatoes are picked, here’s the whole job in short form. Pin it somewhere you’ll see it, because October tends to get busy.
- Look over every plant for disease before anything gets pulled.
- Bag blighted, bacterial or virus-infected plants, and compost only the healthy ones.
- Save seed from your best open-pollinated or heirloom tomatoes.
- If you want a head start, root a few healthy side shoots indoors before frost.
- Chop healthy vines and pick off leftover fruit before they hit the compost.
- Dig up and check the roots of any plant that wilted or struggled.
- Scrub and disinfect cages, stakes and pots before storing them.
- Sow winter rye, add compost or mulch the bed with leaves.
- Pick a new spot for next year’s tomatoes.
