When Potatoes Don't Come Up: Using Drone Imagery to Catch Stand Failures Before Replanting Deadlines

April 20, 2026 · 5 min read ·

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Every year in the Magic Valley, some potato fields simply don’t come up the way they were supposed to. The seed went in on time. The ground was fit. The grower did everything right. And then mid-May arrives and there are gaps — sections of bare soil where emerged plants should be standing.

What happens next depends almost entirely on how fast you can quantify the problem.

A replanting decision carries a hard agronomic deadline. Potatoes planted in SE Idaho need 90 to 110 days to reach maturity depending on variety — Russet Burbank, the dominant variety in the Magic Valley, is on the longer end. The window to replant and still reach maturity before the first fall frost closes somewhere around June 1 in the lower valley, earlier at higher elevations. After that, the math doesn’t work.

That deadline creates a narrow evaluation window in mid-May: after emergence is far enough along to assess, before replanting time runs out. A visual walk of a large field in that window gives you a rough impression. A drone flight gives you a map.

Why SE Idaho Potato Stands Fail

Two risks dominate spring stand failures in the Magic Valley: frost and wireworm.

Frost is the obvious one. Early-planted fields — going in late March or early April to hit the processing contract schedule — are in the ground weeks before the last frost risk has passed. Even in the lower valley around Twin Falls and Gooding, killing frosts can occur into mid-May. A frost event on newly emerged tissue doesn’t necessarily kill every plant, but it can delay or deform emergence enough that gaps are hard to distinguish from true seed failures until the field has had more time to sort itself out.

Wireworm is the less visible risk. The larvae of several click beetle species (Limonius spp. are the most problematic in Idaho) spend years in the soil and feed on seed pieces underground and on emerging stems. Wireworm damage is erratic — a field can have hot spots of severe infestation separated by areas with no detectable pressure. The visual pattern is distinctive: irregular clusters of missing plants with no obvious soil disturbance, often concentrated in areas with wetter soil or more organic matter. You won’t see the damage; you’ll only see the absence it creates.

Both failure modes produce the same result from above: patches of bare ground where canopy should be closing in.

What RGB Drone Imagery Shows You

Stand assessment is fundamentally a counting problem. How many plants emerged? Where are the gaps? How large are they, and are they distributed randomly or clustered in a pattern that suggests a recoverable cause?

This is work that high-resolution RGB drone imagery handles well — and that doesn’t require multispectral sensors. At 1 to 2 centimeters per pixel, which is achievable at low altitude with a standard commercial drone, individual emerged potato plants are clearly distinguishable from bare soil. A flight over a quarter-section field takes less than an hour, and the resulting orthomosaic — a corrected, top-down composite image — gives you a wall-to-wall view of emergence that no ground-based scouting can match in the same timeframe.

The practical output from a stand assessment flight is a spatial map of plant presence and absence across the field. An agronomist or crop consultant working from that map can estimate plant population per acre in different zones, identify gap clusters, and distinguish random emergence variation (normal) from concentrated failure areas (problematic).

For a grower facing a replanting decision, that map is the difference between guessing and knowing.

The Replanting Decision

Not all stand gaps warrant replanting. The general threshold most Idaho consultants work from is a plant population at or above 85% of target as acceptable for most commercial production targets. Below that, the economics of replanting depend on how the gap is distributed, whether the remaining plants are healthy, and how much of the replanting window is left.

A field-wide average, however, can hide an important distinction: 80% population spread uniformly across a field is a different problem than 80% population where half the field is at 95% and a 20-acre section is at 40%. The first case may recover. The second case may warrant partial replanting — or a conversation with your crop insurance agent.

Aerial imagery makes that distinction visible. It also makes the documentation of it defensible.

The Crop Insurance Angle

Federal crop insurance policies covering potatoes — primarily Multi-Peril Crop Insurance (MPCI) through USDA Risk Management Agency — typically require growers to document stand failures before replanting or abandoning acreage. The adjuster needs to verify the extent of the failure. A drone-generated orthomosaic, tied to GPS coordinates and a documented flight date, gives the adjuster a spatially explicit record of the field at the time of failure.

This matters in a couple of ways. First, it protects the grower’s claim by creating a clear, timestamped evidentiary record before any replanting activity disturbs the field. Second, it accelerates the adjustment process — an adjuster working from imagery can triage a claim faster than one waiting to schedule an in-person walk. In a year with multiple field failures across a region, that speed difference can affect when checks arrive.

It also serves the grower’s own documentation beyond insurance. If you’re on a processing contract and need to notify your contractor of a stand failure that will affect delivery volume, imagery-based documentation creates a clearer record than a hand-drawn estimate.

When to Fly

The right timing for a stand assessment flight is when emergence is far enough along to be confident you’re seeing a real population picture — not so early that late-emerging plants haven’t had their chance, not so late that the replanting window has closed.

In the lower Magic Valley (Twin Falls, Gooding, Jerome), that window typically opens in the first two weeks of May for early-planted fields. For fields planted later, the window shifts accordingly. At higher elevations — above 4,500 feet in parts of Minidoka, Power, or Bingham counties — emergence timing lags by one to two weeks and the replanting deadline tightens.

Practical guidance: plan for a flight between 7 and 14 days after you expect 80% emergence. If emergence looks uneven earlier than that, fly sooner — the earlier you have the map, the more options you have.

Don’t wait for a full field walk to confirm the problem you already suspect. If a field looks wrong from the road in early May, it is worth an aerial pass before you’ve run out of replanting calendar.

Key Takeaways

SE Idaho potato stands face real spring risk from late frost and wireworm damage. Both failure modes create gap patterns that are difficult to quantify accurately from the ground.
RGB drone imagery at low altitude produces a plant-level map of emergence across a full field — without requiring multispectral sensors.
The replanting decision has a hard agronomic deadline. The drone flight needs to happen in early-to-mid May to leave any options on the table.
Aerial imagery creates defensible, timestamped documentation for crop insurance claims before replanting activity disturbs the field.
A stand map distinguishes uniform low population (may recover) from concentrated failure zones (may warrant partial replanting) — a distinction that changes the economics of the decision.

Get a Stand Assessment Flight Scheduled

Penrose flies stand assessment imagery for potato producers in the Magic Valley. RGB flights are available now for May scheduling, and our service includes a georeferenced orthomosaic you or your agronomist can use to make the replanting call.

Contact us to schedule your May flight →

Sources: University of Idaho Extension BUL 840 (Potato Production in Southern Idaho); USDA Risk Management Agency, Multi-Peril Crop Insurance policy provisions; USDA AMS National Potato and Onion Report (April 2026); Soil-pest context from University of Idaho Extension CIS 1219 (Wireworm Management in Idaho).