By now many of us are antsy to get roots growing, while some gardens in Baja Arizona are already well underway. Here’s an A-to-Z of what you can plant in March and April, whether you live way up high or way down low.
Remember: Planting calendars aren’t rulebooks. Many things can be planted outside of their ideal planting dates if they’re given special protection or extra attention, or if we have extended seasons of the right weather. Patience is the name of the game this time of year, however. If planted too early, many heat-loving crops will grow more slowly than the same crops planted a bit later, when the temperatures were just right. Even if your timing is impeccable, late cold snaps are common across Baja Arizona so be prepared to protect newly planted spring or summer crops if temperatures take a sudden nosedive.
Asparagus is best planted in early spring so it has some time to get established before the heavy heat of summer. This long-lived perennial grows best in cooler temperatures, so even though it can be planted through mid- to late April across much of Baja Arizona, it’s preferable to plant it after the last frost, when soil temperatures reach at least 50.
Basil thrives in the heat, so you can start it indoors if it’s still cold outside and move it out into the garden once soil temperatures are above 70 and all dangers of freezing are past.
Blackeye, green snap, lima, pinto, soy, and yardlong beans can all be planted throughout March and April in the lowest elevations of Baja Arizona. Wait until there’s no more danger of frost and soil temperatures are above 65, and be sure to protect them from any late cold snaps at mid to higher elevations. Blackeye and yardlong are especially heat-loving, with a longer planting window than the other spring beans.
It’s already a bit too hot to plant beets at the lowest elevations, but those of you in the 1,000 to 3,000 feet elevation range should aim to get them planted by mid-March or early April. The season for this root veggie is just getting started at 3,000 to 4,500 feet, so those of you around Willcox and Benson have until around mid-May to plant.
Broccoli and cabbage like cooler temperatures, so they can only be grown at the highest elevations of Baja Arizona this time of year. You can begin planting broccoli around mid- to early April if you live above 3,000 feet. Cabbage seed should be started by mid-March to mid-April, and transplants can be moved into the garden four to six weeks later, when temperatures are above 60.
If you live below 2,000 feet, you can continue planting cantaloupe until early to mid-April. Tucsonans and others at 2,000 to 3,000 feet can start planting them in mid-March through early June, after the last frost. It still needs to warm up a bit more to plant them at higher elevations.
You can still plant carrots until mid-March at 2,000 to 3,000 feet, and a spring crop can be started now if you live between 3,000 and 4,500 feet.
Cauliflower is another of the cool-season crops that has enough time to mature before the heat of summer only at the higher elevations of Baja Arizona, above 3,000 feet. Seed can be started indoors five to seven weeks before the last frost and transplanted once the danger of frost is past.
Chard can be planted now at mid to higher elevations. Above 2,000 feet, continue planting through the beginning of April, and until mid- to late April above 3,000 feet. For the best flavor, aim for about 50 to 60 days of growth before temperatures climb above 90.
There’s a short window in which you can grow sweet corn if you live between 1,000 and 3,000 feet: now through mid-March at the lower end of that range, and from mid-March until early April at the higher.
Plant cucumber and eggplant once soil temperatures are above 65 and there’s no more danger of frost. You can continue planting them through early April below 2,000 feet, and from late March through mid-May if you’re at an elevation of 2,000 to 3,000 feet. If you live above 3,000 feet, seed can be started indoors in early to mid-April to get a jump on the season. Make sure to protect these heat-loving plants if we get a late cold snap!
Continue planting endive and escarole above 3,000 feet until early April, and begin planting it around mid-April if you live above 4,500 feet.
Although garlic is a fall crop for many of us, bulbs can be planted until around mid- to late April above 3,000 feet.
Horseradish dislikes rapid cycles of freezing and thawing, and does its best growing in late summer to early fall. If you live above 3,000 feet, wait until the danger of freezing is past but get them in the ground before it gets too warm. It may already be too warm to plant horseradish at Tucson’s elevation unless we have a long, cool spring. It generally stays too warm below 2,000 feet to have much success growing this perennial.
Kale, kohlrabi, leek, and lettuce are all cool-season veggies, so there’s still some time left to grow them at middle to higher elevations. Leaf lettuce can be planted until early April at 2,000 to 3,000 feet, and until mid-April above that elevation. Head lettuce can be planted until mid-March at 3,000 to 4,500 feet. Those above 3,000 feet can plant kale until late March or early April, kohlrabi from early April to mid-May, and short-season leek varieties until mid- to late April.
Keep planting muskmelon at the lowest elevations until early or mid-April, but wait until after the last frost if you’re in Tucson or surrounding areas at 2,000 to 3,000 feet. The season begins around the beginning of April at this elevation, but seeds can be started indoors three to four weeks earlier and transplanted into the garden after the last frost.
Though we’re done planting mustard at middle to lower elevations of Baja Arizona, the season is just getting started at higher elevations. Continue planting through mid-July at 3,000 to 4,500 feet, and begin planting around the beginning of April through early July above 4,500 feet.
Now through mid-April is the best time to plant okra at the lowest elevations. You have until early to mid-June if you’re at 1,000 to 3,000 feet elevation, but wait until after the last frost to plant them.
Onions like cooler weather, so planting season is finished at lower elevations and harvesting is underway, or will be shortly. Above 3,000 feet, green or bunching onions can be planted until around late April. Bulbs can set out until mid-March up to 4,500 feet, and in early April above that elevation.
Parsley can be planted through mid-April only at the highest elevations this time of year.
You can start planting parsnip around the beginning of April if you live above 4,500 feet.
Peas are spring crops that grow best when the soil temperature is around 60. You should have until around early to mid-March to plant them in the Tucson area and slightly lower elevations.
The lowest elevations of Baja Arizona are able to plant pepper starts now and into the summer, though earlier planting dates are ideal. Seeds need six to eight weeks before they’re ready to transplant, so start your seed soon or purchase plants from your local nursery and plant them after the last frost if you live above 2,000 feet.
Potato can be planted from 1,000 to 3,000 feet this time of year. You have until mid-March at the lower end of that elevation, and until the end of April at the higher end. Start planting sweet potato if you live below 2,000 feet, making sure to protect them from any late cold snaps.
Begin planting pumpkin in early March at the lower elevations, and around early April at 2,000 to 3,000 feet.
Everyone in Baja Arizona can grow radish this time of year. Continue planting it until early to mid-April at lower elevations, until late April at mid-level elevations, and begin planting it in early March and April at higher elevations.
We’re usually done planting rhubarb, rutabaga, salsify, and spinach by early March below 3,000 feet, but they can all be planted now or soon above that elevation. Begin planting rhubarb in early March and salsify around mid-March, and continue planting spinach through mid-April. Begin planting spinach along with rutabaga and salsify in early April at the highest elevations.
Both summer and winter squash can be planted now through at least mid-July at the lowest elevations. Those of us at mid-Tucson’s elevation begin planting around middle to late March.
Keep planting tomato starts until mid-March in the lowest desert areas, and begin planting them around the same time in the 2,000 to 3,000 feet range. Areas that lie above that elevation can start seed indoors from early March to early April.
You may be able to get by with planting turnips around Tucson if we’ve had a mild year and you act quickly. Otherwise, they can be planted from early March to mid-April above 3,000 feet, and from early April to mid-May above 4,500 feet.
It’s warm enough to plant watermelon in the low to middle elevations of Baja Arizona. Directly sow seeds or place transplants once the soil temperature is above 70. ✜
Information compiled from Arizona Master Gardener Manual (published online); Gardening in the Deserts of Arizona by Mary Irish; Extreme Gardening: How to Grow Organic in the Hostile Deserts by David Owens; Low Desert Planting & Harvest Calendar (published online) by Urban Farm; and personal interviews.
Amy Belk is a garden writer and photographer, a certified arborist, and a certified nursery professional who has been learning from her garden for 15 years. She and her husband homestead on a little piece of the desert in the heart of Tucson.