Mint in Zone 8A — Desert Southwest

Mint is a fantastic addition to any Desert Southwest garden. The fresh, vibrant flavor elevates everything from summer drinks to savory dishes. Plus, the satisfaction of snipping your own homegrown mint for a refreshing iced tea on a scorching day is hard to beat.

While our extreme heat and arid climate present challenges, mint is surprisingly adaptable with the right care and timing. Our long, 265-day growing season gives you ample opportunity to enjoy a bountiful harvest.

Starting mint from seed indoors in the Desert Southwest is an option, but not always necessary. It's really only worth it if you're after a specific variety you can't find locally. If you want to start from seed, do so in early to late January, about 8 weeks before transplanting.

Use seed trays with a good seed-starting mix. Keep them consistently moist (bottom watering is great for this) and provide warmth and light. Remember, our springs here in the Desert Southwest can come on fast, so be ready to get those seedlings outdoors when the time is right!

Transplanting mint outdoors in the Desert Southwest should happen in early March through early April. Before you plant, harden off your seedlings by gradually exposing them to outdoor conditions for about a week. Space plants 18-24 inches apart.

The weather during this time can be unpredictable, with potential for late frosts or sudden warm spells. Keep an eye on the forecast and be prepared to cover your young plants if needed. Many gardeners find that buying starts or getting divisions from other gardeners is the easiest way to go. Also, be warned: mint spreads aggressively, so consider planting it in containers to keep it under control.

Mint loves moist soil, which can be tricky to maintain in our Desert Southwest climate. During the active growing seasons (spring and fall), water deeply about 2-3 times per week. Use the "finger test" – if the top 2 inches of soil are dry, it's time to water.

In the peak of our extreme summer heat, you might need to water almost daily, especially if your mint is in full sun. During the monsoon season (late summer), let the rains do some of the work for you, but supplement as needed. Aim for about 1-2 inches of water per week, whether from rain or irrigation.

Water at the base of the plant to avoid wetting the leaves, which can encourage fungal diseases in our arid environment. Signs of underwatering include wilting and yellowing leaves. Overwatering can lead to root rot, so make sure your soil is well-draining. A layer of mulch, like shredded bark or compost, will help retain moisture and regulate soil temperature.

Pruning mint is essential, especially in the Desert Southwest, to keep it from taking over your garden and to encourage healthy growth. The goal is minimal focused pruning. Throughout the growing season, regularly harvest entire stems, cutting them back to just above a leaf node. This encourages bushier growth.

Pinch off any flower buds as soon as you see them to keep the plant focused on leaf production. As the first frost approaches in late November, give your mint a final haircut, cutting it back to a few inches above the ground. This helps it conserve energy over the winter.

You can expect your first mint harvest in the Desert Southwest from early May through late June, about 60 days after transplanting. The leaves are most flavorful before the plant flowers, so keep an eye out for those buds. Harvest leaves and stems anytime you need them.

To harvest, simply snip off stems with scissors or garden shears. Avoid pulling leaves off individually, as this can damage the plant. Pinching off the flower buds encourages continued leaf production, giving you a longer harvest. As the first frost approaches in late November, harvest any remaining leaves and dry or freeze them for use during the winter months.

Here are some common problems you might encounter with mint in the Desert Southwest:

Rust

• What it looks like: Rusty orange, yellow, or brown pustules on leaves and stems, mostly on undersides. Leaves yellow and drop prematurely.
• What causes it: Rust fungi thrive in warm, humid conditions. While we're arid, monsoon season can create enough humidity for rust to take hold.
• How to fix/prevent it: Remove affected leaves immediately. Avoid overhead watering. Improve air circulation by spacing plants properly. Apply sulfur or copper fungicide if needed. Rotate crops to prevent buildup in the soil.

Spider Mites

• What it looks like: Fine stippling on leaves (tiny white dots). Fine webbing on leaf undersides and between stems. Leaves turn bronze or yellow.
• What causes it: Spider mites thrive in hot, dry conditions, which we have in abundance. They're especially problematic during periods of drought stress.
• How to fix/prevent it: A strong water spray (daily for a week) is often the best treatment. Increase humidity around plants. Neem oil or insecticidal soap can also be effective. Release predatory mites for a natural solution.

Invasive Spreading

• What it looks like: Mint popping up everywhere you don't want it! Runners spreading under the soil and sending up new shoots.
• What causes it: Mint is a vigorous grower and spreads aggressively via underground runners.
• How to fix/prevent it: Plant mint in containers to contain its spread. Regularly check for and remove any runners that escape the container. Be vigilant about pulling up any unwanted shoots.

Powdery Mildew

• What it looks like: White or grayish powdery coating on leaves, stems, and sometimes fruit. Leaves curl, yellow, and die.
• What causes it: Powdery mildew thrives in warm days, cool nights, and moderate humidity.
• How to fix/prevent it: Improve air circulation through spacing and pruning. Remove affected leaves. Neem oil or potassium bicarbonate sprays can help. Milk spray (1 part milk to 9 parts water) is surprisingly effective.

Desert Southwest Specific Challenges: The extreme heat and arid humidity of the Desert Southwest can stress mint plants, making them more susceptible to pests and diseases. Monitor your plants closely and adjust your watering and care as needed. During monsoon season, be extra vigilant about fungal diseases.

Mint can be a great companion plant in the Desert Southwest, but be mindful of its spreading habit. It's great planted near tomatoes and peppers, as its strong scent can help deter pests like aphids and flea beetles, which are common in our gardens. It also benefits cabbage and broccoli by repelling cabbage moths.

Avoid planting mint near parsley or chamomile. Mint can inhibit the growth of parsley. Chamomile likes dry conditions, which is the opposite of mint's preference. Always keep mint contained to prevent it from overtaking its companions.