Do you want to grow watercress in Hawaii, but don’t know when to plant them?
Planting watercress is not as easy as it seems.
- Watercress are not able to survive frost or cold weather under 50 degrees Fahrenheit.
This shouldn’t be a problem in Hawaii. You won’t have to worry about planting too early or too late on any island in Hawaii.
Today, I’m going to teach you the ideal time to plant watercress in Hawaii:
- To Learn More About HOW to Grow Watercress, Check Out This GUIDE!
When to Plant Watercress in Hawaii
As you may have already guessed, you need to pay very close attention to your local weather in the spring. Specifically, you are going to need to watch when the last frost occurs.
In general, when there hasn’t been a frost for two weeks, you are SAFE to plant your watercress outside in Hawaii!
For your reference, I have created this table for average frost dates for most major cities in Arizona. If your city is not listed below you can find its Last & First Frost Dates HERE.
Hawaii Last & First Frost Dates
Unfortunately, Mother Nature plays cruel tricks on us every year.
It should be noted that the above dates are just averages.
There are years when the last frost comes MUCH later. Sometimes, the last frost happens much earlier and you can get your watercress planted outside in Hawaii much quicker.
Like I said before, you need to be very diligent in checking your local weather.
So what happens if a frost comes AFTER you plant your watercress?
When you know a frost is coming you need to take action.
- If watercress are in pots, bring them inside
- If watercress are in the ground, cover them in burlap and hope they survive
Also, make sure not to plant your watercress in your garden too late.
- Planting watercress too late will cause small watercress or even worse, no watercress.
When Should You Start Your Watercress Seeds Indoors?
Depending on the type of watercress, it takes roughly 15-20 days to grow watercress from seed indoors and then transplant them to your garden.
For a specific date that you should start watercress seeds indoors you should:
- Find the last average frost date HERE
- And then subtract 20 days from it
Not only this, but I recommend again paying close attention to your local weather report. For Hawaii though, I recommend starting your seeds indoors during late winter.
It should also be noted that the best technique for bringing your watercress plants outside is to introduce them (in their pots) outside for an hour. And then increase the amount of time they spend outside each day by an hour until they have been outside for 8 hours.
This will “hardened” your watercress plant, increasing its chances of fighting off diseases, insects, droughts, and wet conditions.
If you want to learn WHEN to plant ANY Vegetable in Hawaii, head over to HERE and just type in the vegetable you want to grow.