Planting zone for 21085 — Joppa, MD
ZIP code 21085 (Joppa, Harford County) is in USDA zone 7b: the coldest winter night averages 5 to 10 °F. The median last spring frost is April 10 and the first fall frost October 30.
Where ZIP 21085 is
Outlined: the ZIP code area · tap the map for the zone at any spot · scroll or pinch to zoomNot the official USDA Plant Hardiness Zone Map. Zones come from the 2023 USDA hardiness-zone data by the PRISM Group, Oregon State University; we re-mapped and recolored them. The official map is at planthardiness.ars.usda.gov.
Was 7a on the 2012 map — half a zone warmer now. The zone is the one at the center of the ZIP code; hilly ZIPs can span two zones. What zone 7b means →
Frost forecast — next 7 nights
live from the National Weather ServiceLoading the forecast for Joppa, MD…
Forecast data: National Weather Service (api.weather.gov), public domain. This is not a warning service — for official frost and freeze warnings see weather.gov.
Frost dates in Joppa, MD
A hard freeze (28 °F) usually ends around March 29 and returns around November 10.
From the NOAA station Aberdeen Phillips Field, MD — 10 miles away, elevation 56 ft. NOAA NCEI U.S. Climate Normals 1991–2020, 32 °F threshold. Low spots and valleys can freeze later in spring than the station.
When to plant vegetables in 21085
Counted from the median last spring frost (Apr 10) and first fall frost (Oct 30) with the rules of thumb U.S. extension services publish. Cool-season crops take a light frost; warm-season crops do best once the soil is above about 60 °F.
When spring arrived in 2026
In 2026, spring leaf-out near 21085 came on Mar 15 — about the same time as the 1991–2020 average (Mar 15).
Mar 152026
Mar 15
The Spring Index marks the day when accumulated warmth is enough for lilac and honeysuckle to leaf out — a widely used signal that the growing season has started. Source: USA National Phenology Network, www.usanpn.org — Spring Indices, first leaf, 2026 (data as of 2026-09-08) and 30-year average 1991–2020 (CC BY 4.0).
Soil in Joppa, MD
The soil mapped at the center of ZIP 21085 is Russett — fine sandy loam, moderately well drained.
Map unit: Russett fine sandy loam, 0 to 5 percent slopes.
Soil Survey Staff, Natural Resources Conservation Service, USDA. Soil Survey Geographic (SSURGO) Database, via Soil Data Access, accessed 2026-10-29. The soil at the center point of ZIP 21085; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.
Climate in Joppa, MD
Average high and low, by month
Precipitation by month inches
NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Aberdeen Phillips Field, MD (10 mi away); precipitation: Kingsville 1.2 E, MD (2 mi away). Daylight is calculated from latitude.
Nearby ZIP codes
2 of the 8 nearest ZIP codes are in a different zone — elevation and distance from water change winter lows quickly.
Questions about 21085
What planting zone is ZIP code 21085?
ZIP code 21085 (Joppa, MD) is in USDA hardiness zone 7b on the 2023 map: the coldest night of an average winter reaches 5 to 10 °F (−15 to −12.2 °C).
When is the last frost in Joppa, MD?
The median last spring frost (32 °F) near 21085 is April 10; after April 30 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Aberdeen Phillips Field station.
When is the first frost in Joppa, MD?
The median first fall frost near 21085 is October 30, giving a median frost-free growing season of 201 days.
When should I plant tomatoes in 21085?
Start tomato seeds indoors around Feb 13 – Feb 27 and set transplants outside around Apr 17 – May 1, one to three weeks after the median last frost.
How much rain and snow does 21085 get?
About 50 inches of precipitation a year (NOAA 1991–2020 normals, Kingsville 1.2 E station).
How hot do summers get in Joppa, MD?
The average high peaks at 86 °F in July, with about 26 days a year at 90 °F or more.
What kind of soil does 21085 have?
The USDA soil survey maps Russett at the center of ZIP 21085: fine sandy loam, moderately well drained, pH about 3.9 (strongly acidic).
Did spring come early in Joppa, MD in 2026?
Spring leaf-out near 21085 came on Mar 15 in 2026, about the same as the 1991–2020 average (Mar 15), according to the USA National Phenology Network Spring Index.
What kind of onions grow in Joppa, MD?
Intermediate onions: the longest day near 21085 is 14 h 57 min, so day-neutral types bulb best; long-day varieties may not bulb fully.
Did the zone for 21085 change?
Yes. The 2012 USDA map put 21085 in zone 7a; the 2023 map puts it in zone 7b. The newer map uses 1991–2020 data and more weather stations.