What should I plant in March in Denver, CO?

In March in Denver, CO (zone 5b), you can plant Chives, Cilantro, Mint, Oregano, Parsley, and more. These dates are based on local climate data for your area.

When do I plant Chives in Denver, CO?

In Denver, CO (zone 5b), Chives: start seeds indoors Feb 15 – Apr 15, transplant outdoors Apr 24 – Jun 23.

When do I plant Cilantro in Denver, CO?

In Denver, CO (zone 5b), Cilantro: direct sow Mar 17 – Jun 15 and Sep 1 – Sep 23.

When do I plant Mint in Denver, CO?

In Denver, CO (zone 5b), Mint: start seeds indoors Feb 22 – Apr 23, transplant outdoors Apr 24 – Jun 23.

What to Plant in March

Denver, CO · Zone 5b

Last frost: May 5 Frost-free days: 154

Full year calendar for Denver

Spring is still weeks away outdoors, but indoor seed starting is in full swing. Start tomatoes, peppers, and herbs under lights. Prepare beds for cool-season crops that go out next month.

March at a Glance

Indoor Transplant Direct Sow

1 5 10 15 20 25

Chives

Cilantro

Mint

Oregano

Parsley

Sage

Thyme

Artichoke

Beet

Broccoli

Brussels Sprouts

Cabbage

Carrot

Cauliflower

Celery

Kale

Leek

Lettuce

Onion

Peas

Radish

Spinach

Strawberry

Swiss Chard

Turnip

Start Indoors 19

Start these seeds indoors under grow lights or on a sunny windowsill.

Plant now

Brussels Sprouts

Jan 1 – Mar 8

1 per sq ft 80–110 days

Leek

Feb 1 – Mar 16

4 per sq ft 90–150 days

Onion

Feb 1 – Mar 16

9 per sq ft 100–120 days

Celery

Feb 8 – Apr 23

4 per sq ft 80–120 days

Chives

Feb 15 – Apr 15

9 per sq ft 60–90 days

Parsley

Feb 15 – May 8

4 per sq ft 70–90 days

Mint

Feb 22 – Apr 23

4 per sq ft 60–90 days

Thyme

Feb 22 – Mar 31

4 per sq ft 70–90 days

Artichoke

Feb 22 – Apr 8

1 per sq ft 85–100 days

Broccoli

Mar 1 – May 23

1 per sq ft 60–100 days

Cabbage

Mar 1 – May 23

1 per sq ft 70–100 days

Cauliflower

Mar 1 – May 23

1 per sq ft 55–100 days

Oregano

Mar 9 – Apr 23

1 per sq ft 60–90 days

Sage

Mar 9 – Apr 8

1 per sq ft 75–90 days

Kale

Mar 9 – Jun 23

1 per sq ft 50–65 days

Strawberry

Mar 9 – May 8

4 per sq ft 60–90 days

Later this month

Lettuce

Mar 24 – May 16

4 per sq ft 45–60 days

Spinach

Mar 24 – May 8

9 per sq ft 35–50 days

Swiss Chard

Mar 24 – Jul 16

4 per sq ft 50–60 days

Direct Sow 6

Plant these seeds directly into the soil outdoors.

Cilantro

Mar 17 – Jun 15

9 per sq ft 30–45 days

Turnip

Mar 17 – Sep 23

9 per sq ft 30–60 days

Beet

Mar 24 – Sep 8

9 per sq ft 50–70 days

Carrot

Mar 24 – Jul 31

16 per sq ft 70–80 days

Peas

Mar 24 – Jun 30

8 per sq ft 55–70 days

Radish

Mar 24 – Jun 15

16 per sq ft 22–30 days

March Gardening Tips

Start Lettuce, Broccoli, Cabbage indoors now to give them a head start before transplanting outside.
Direct sow Carrot, Peas, Beet straight into the garden — no transplanting needed.
Add compost to beds now so nutrients are available when planting time arrives.