05/13/2026
Many of you have potatoes that are almost ready for harvesting. I’m going to re-post my dehaulming instructions for you.
Dehaulming (also known as "vine killing" or "topping") is the practice of removing or killing the above-ground stems and leaves of the potato plant before you actually dig the tubers out of the ground.
Dehaulming is particularly important in the southern states where disease and pests are an issue.
While hilling is about the beginning and middle of the plant's life, dehaulming is the final act that prepares the potato for long-term survival in your pantry.
In the commercial world, this is often done with chemicals or massive mowers, but in a home garden, it is usually done with a pair of loppers or a scythe. There are four critical reasons to do this...
This is the most important reason for storage potatoes. As long as the plant is green and growing, the potato's skin is thin and fragile ("slipping skin"). When you dehaulm, you send a signal to the tuber that the growth cycle is over. The plant's "skin" (the periderm) begins to thicken and chemically bond to the flesh of the potato.
After 10-14 days of sitting in the soil without a haulm (stem), the skin becomes tough enough to withstand being handled, bagged, and stored without bruising or rotting. So, proper dehaulming helps to increase the yield in terms of tuber size and also MINIMIZE INJURIES DURING POST HARVEST HANDLING because the tuber's skin is properly set and thickened.
Dehaulming HARDENS the potato tubers and INCREASES THEIR SHELF LIFE. After dehaulming, tubers are LEFT BURIED in the field for 10-21 days for the skin to HARDEN, and this reduces injuries during HARVESTING & HANDLING afterwards.
*Weight loss of the potato tuber is one of the significant factors that determines the STORABIILITY of potato tubers.*
Weight loss was almost non-existent in potatoes harvested 9-10 days after dehaulming, while potatoes harvested at 0 days after dehaulming lost the MOST weight, which causes them to not store as well. Reducing sugar, phenol content, dry matter, free amino acids, etc. determines the quality of potatos and dehaulming helps to maintain optimum level for these elements. In addition, it also plays a significant role in plant protection.
Also, If your garden is hit by Late Blight (the fungus Phytophthora infestans), the spores usually start on the leaves. If you leave the dying, infected foliage on top of your potatoes, the spores can wash down into the soil and rot your tubers. By cutting and removing the haulms as soon as you see blight or when the plant starts to naturally yellow, you "cut off" the path of infection before it reaches the crop.
If you are growing a variety that tends to get "hollow heart" (a gap in the middle of large potato varieties) or if you prefer uniform, medium-sized "B-grade" potatoes, dehaulming allows you to stop time.
Dehaulming kills the "engine" of the plant, stopping any further growth immediately. Attempting to dig through a massive, tangled canopy of 4-foot indeterminate potato vines is a nightmare.
Dehaulming clears the field, making it easy to see exactly where the main stem is so you don't accidentally slice through a potato with your shovel.
Timing is everything. You want to wait until the plant has done most of its work, but hasn't yet started to rot. To maximize your harvest and ensure your potatoes survive storage, you can follow this dehaulming (vine killing) schedule. This timeline is based on Days to Maturity rather than the misleading "determinate/indeterminate" labels. Regardless of the variety, the Golden Rule is to wait 10-14 days after dehaulming before you dig to allow the skins to toughen up (set).
-For early season varieties(Yukon Gold, Norland), the dehaulming window is 60-75 days after planting. The flowers have faded but the foliage is green and lush. If you want these for fresh eating as "new" potatoes, you do not need to dehaulm; simply harvest 2-3 weeks after flowering.
If you intend to store them, cut the stems when the plant is at 70-80 days old. Let them sit in the soil for the full 14 days post-dehaulming to prevent the thin skins from "slipping."
-For mid-season varieties (Kennebec, Red Pontiac), the dehaulming window is 80-95 days after planting. The lower leaves being to yellow, and the plant may look "tired". If you dig a couple of tubers and find the potatoes are already at your preferred size, dehaulm immediately to stop further growth.
-for late-season varieties (Burbank Russet, German Butterball), the dehaulming window is 100-120 days after planting. These plants are designed to stay green for 135+ days. If your local frost date is approaching, dehaulm at least two weeks before the first hard frost to prevent cold damage to the tubers. Late varieties are in the ground longest and are most susceptible to blight; remove the haulms immediately if you see leaf spots to protect the underground crop.
Cut the stems about 1-2 inches above the soil line. Do not dig them yet. Leave the tubers in the ground for 10 to 14 days. During these two weeks, do not water the area. You want the soil to be relatively dry, which helps the skin "cure" and prevents pathogens from traveling through the soil.
Manual dehaulming is superior in two specific scenarios. Sometimes, a late-season potato (like a Russet) will stay green and lush right up until the first hard frost. If you wait for frost to kill it, the sudden cold can actually damage the tubers near the surface. Manually dehaulming two weeks before your expected frost is a safer bet. Or if Colorado Potato Beetles or Blight are winning the war late in the season, dehaulming allows you to save the crop you have rather than letting the pests weaken the tubers.
