How to Grow Baby Rocket (Arugula) In Warm Tropical Climates

I’ve been asked several times if we can  grow rocket (also called ‘arugula’) in Metro Manila.   My usual response was a bit of skepticism because I know that rocket is a cool weather plant that grows best in the uplands.  In Manila, the best time to start growing arugula is from November to early January, or when the maximum temperature throughout the day typically does not exceed 30 degrees Celsius.   They can still thrive  during other months,  but the extreme heat (especially during summer) often causes the leaves to taste unpalatably bitter.   So during these times, I would harvest them as baby rockets,  while the leaves are still very young and tender. 

 

Not everyone enjoys the taste of arugula.  Some people (like my daughter) actually hate it.  But for me, I love the pungent aroma whenever I add it to my pizza or salad. Its flavor also gives my pasta dish a flavorful twist.

Starting from Seeds

I usually start growing arugula by sowing a few seeds directly on the soil bed or containers filled with potting mix and compost material. The plant has shallow roots and therefore, it can be grown in any small to medium- sized container.  After two weeks,  pull out some of the seedlings to avoid overcrowding the pot. Water deeply at the roots every other day, or more often if the soil tends to dry out faster.

Plant Care

Choose a spot where the plant gets at least 3 hours of early morning sun. Protect it from extreme heat by providing some dappled shade.  This plant can not tolerate drought so keep the soil consistently moist by watering regularly.  The leaves are prone to leaf miners and other common garden pests. To treat, spray neem oil (diluted in water) at least once a week.

Harvesting the leaves

Rocket should be ready to harvest in as early as 15-30 days.  If you want to harvest them as baby rockets, harvest the young leaves before they start to mature, or within 2-3 weeks. Mature leaves are darker and more wrinkled than the young leaves.  To harvest, simply cut the leaves individually at the base.

Why arugula leaves taste too bitter?

In warm climates, arugula gets more pungent or bitter.  The pungent taste comes from the high level of sulfur in the plant, which is a natural defense mechanism to deter predators. The leaves turn more bitter as they mature and get exposed to the sun’s heat. In the Philippines, outside temperature gets as high as 38 degrees Celsius during summer.  During summer, rocket leaves may get distastefully bitter. To minimize this, here are a few tips:

Provide some shade. Plant arugula in an area that gets early morning sun or some dappled shade. Arugula can tolerate some shade, but make sure to place them in a well-lit area where the plants can get exposed to indirect sunlight.

Do not wait too long.   Or maybe,  consider harvesting them as microgreens.  As microgreens, you can still get that mild peppery flavor of arugula.  Another option is to  wait a little bit longer and harvest them as baby rocket greens.

Water often. Make sure to keep the soil moist all the time, but not soggy. Consider mulching the soil with dried leaves or rice hull to slow down moisture evaporation.

Wait it out.  Wait until the peak of  this hot summer season is finally over.  Once the rainy days start and the average temperature cools down, usually around the last week of May, you may start sowing your arugula seeds. If you have already planted a fully grown arugula, prune mature leaves regularly  so the plant will continue to grow new leaves.

Happy gardening!