Start these roots when the soil has warmed, not the day the last frost passes. New Mexico gives gardeners a long season on paper, but heat, dry air, and elevation shape the crop more than winter does. The details below cover the dates, the length of the window, and the water question. They also explain why this page names no varieties. For the crops themselves, see Celeriac, Kohlrabi, Horseradish and Jerusalem Artichokes.
When the soil is warm enough in New Mexico
At the Albuquerque reference station, NOAA’s 1991-2020 U.S. Climate Normals put the last spring freeze (32°F) between March 31 and April 12. That range is the 30-70% probability band, so a freeze after it is always possible. It describes the airport, not your yard. Suburban and rural gardens usually see the last spring frost one to two weeks later, and elevation pushes it later still. Check your own county before you mark a calendar.
Treat that date as a proxy and nothing more. Celeriac, Jerusalem artichokes, and horseradish wait for warm soil, and soil warms after the frost risk ends, not along with it. Air can climb into the 60s by day while the ground a few inches down is still cold from winter. A celeriac transplant set into cold soil sulks and stalls. A tuber or root piece buried too early sits dormant and is exposed to rot. A cheap soil thermometer pushed in to planting depth each morning is more honest than any date, and your extension office can tell you what soil readings suit each crop.
The cool-tolerant roots behave differently. Kohlrabi, turnips, and rutabagas accept cooler ground and can go in earlier, which suits New Mexico because they want to be finished before summer heat arrives. The warm-soil group goes in afterward. That order comes up again when you plan the year.
Site Jerusalem artichokes before you plant them
Jerusalem artichoke is effectively permanent once planted. Every fragment of tuber left in the ground regrows, and digging never gets them all. Many gardeners regret this planting more than any other in the vegetable garden. Choose a spot you will never want for anything else: a back corner, a bed bounded by a wall or pavement, or a large sunken container that you accept you will fight with indefinitely. Do not put it in a bed you plan to rotate.
Plant the tubers only after the soil has warmed, and expect them to tolerate the cold end of New Mexico’s winters. Horseradish deserves similar respect. A root piece left behind sends up a new plant, so give it its own corner too.
How long the season lasts here
The same NOAA normals give the first fall freeze at the Albuquerque station between October 29 and November 9. Subtract the spring dates from those and the frost-free window runs from about 200 days (April 12 to October 29) to about 223 days (March 31 to November 9). Those are reference-station figures. A garden in a cold-air pocket or in the mountains can lose a week or two at each end, and more with elevation. Your own window may be well under that range.
A window that long allows things a short one does not. It leaves room for a second sowing of the quick roots. Kohlrabi and turnips sown in late summer mature in cooling weather, and in much of New Mexico that fall crop is the easier one, since the spring crop races the heat. The window also gives celeriac, the slowest crop in this group, room to finish. It still needs transplants started indoors well ahead of the last frost, and then set out once the soil has warmed.
Transplanting also raises the root check question. Turnips, rutabagas, and kohlrabi form roots that dislike disturbance, so they are better sown where they will grow. Celeriac is the exception, and a long window makes transplanting worth the care of handling a seedling’s roots gently. At a short-season mountain site the logic flips. The first sowing is the only sowing, and a transplant that sulks for two weeks costs a real share of the season. Ask your county extension office how long celeriac needs in your area before committing.
For how to stagger sowings across the window, use the succession sowing guide on this site. The first fall frost also does not end the harvest. Hardy roots can stay in the soil past it, which the next section covers.
Heat and water in New Mexico
Two numbers would normally anchor this section: days above 90°F and summer rainfall at a reference station. This page does not carry verified figures for either, and a guess would be worse than a gap. Look up your nearest station in the NOAA normals, or ask your extension office, before you plan summer watering. The pattern is easy to describe without them. Roots swell best on steady moisture, and a dry, hot stretch followed by a soaking produces cracked, woody, or hollow roots. Kohlrabi turns tough in heat, and celeriac sulks without constant water. Mulch over the root zone and drip irrigation do more here than any variety choice. If you garden in Arizona’s neighbor state and have read Growing Unusual Root Crops in Arizona, the principle is the same, only less extreme at most New Mexico elevations.
The winter figure we do have is the mean daily minimum of the coldest month at Albuquerque: 26.4°F. It is an average of nightly lows, not a record cold snap, and it says the ground there does not stay frozen solid all winter. The USDA Plant Hardiness Zone Map (2023) covers New Mexico with a wide range of zones, from 4b to 9a, so a gardener in the northern mountains and one in the southern valleys are living in different worlds. Take the zone for your own county, not the territory range.
That winter low decides what can stay in the ground. Horseradish and Jerusalem artichokes are perennials that handle cold well, and under a layer of mulch they can overwinter where the soil does not freeze deep. The hardy roots, such as turnips and rutabagas, can also be held in the ground under mulch in the milder valleys. In colder, higher gardens, lift them and store them before the soil freezes hard. Celeriac is less forgiving than the rest of the group, so lift it before a hard freeze.
Storage touches food safety, so inspect every root before it goes in and while it sits. Keep any root with damage or soft spots out of the store. A soft patch, a weeping spot, or a moldy crown ends the question, however sound the rest looks. Do not trust a root just because it looks firm elsewhere, and do not count on a fixed keeping time. Check stored roots regularly and discard any that turn.
Which these root crops suit New Mexico
Choose by type first. New Mexico’s long but dry and variable season favors the cool-season roots timed to dodge midsummer heat, and the permanent perennials that shrug off the cold. Here is how the five fit:
| Type | Fit for New Mexico | What to watch |
|---|---|---|
| Kohlrabi | Good for spring and fall sowings that avoid midsummer | Woodiness and bolting in heat |
| Turnip and rutabaga | Suited to fall crops and cooler spots | Brassica pests and diseases; heat stress |
| Celeriac | Needs the long window and steady water | Transplant timing; uneven moisture |
| Horseradish | Cold-hardy perennial; handles winter well | Spreads from root fragments |
| Jerusalem artichoke | Cold-hardy and vigorous | Permanent once planted; digestive effects |
Turnips and rutabagas are brassicas. They share their troubles with cabbage, kale, and mustard, so a gardener who rotates them into a cabbage bed has rotated nothing. Keep them out of any bed those crops used recently, and follow the rotation page on this site.
Jerusalem artichokes cause digestive discomfort in many people, because they store inulin instead of starch. That is a plain fact of the vegetable, not a verdict on it. A small first portion is the sensible way to find out how you react. Horseradish has its own preparation hazard. Grating a fresh root releases compounds that burn the eyes and airways, so ventilate the room well and keep your face away from the bowl.
This page names no cultivars, and that is deliberate. Variety performance depends on elevation, soil, and water, and the only recommendations that mean anything are those trialled where you garden. This page does not have those trial results. The New Mexico State University Cooperative Extension Service does, so start there. For a very different case, where humidity makes disease resistance the first criterion, compare Growing Unusual Root Crops in North Carolina.
Common questions
Can I grow celeriac in New Mexico?
Often yes, if the season is long enough where you garden and you can keep the water steady. At the Albuquerque reference station the frost-free window runs from about 200 to 223 days. Higher or colder sites have less, so check with your county extension office first.
When should I plant Jerusalem artichokes?
After the soil has warmed, which comes after the last frost date, not on it. Decide where they go first, because they come back from any tuber left in the ground.
Do I lift roots in winter or leave them in the ground?
It depends on how hard your soil freezes. Hardy perennials like horseradish and Jerusalem artichokes can stay under mulch where winters are mild. Celeriac and other roots in colder, higher gardens should be lifted before a hard freeze, then inspected closely, because a soft patch or moldy crown means that root should not be eaten.
Do the frost dates here apply to my garden?
Only roughly. The dates come from the Albuquerque airport station, and gardens elsewhere often see the last frost one to two weeks later and the first fall frost earlier, especially at elevation. Your county extension office can give you local figures.