Watercress Expirement, 4 weeks later

(Actually it has been 5 weeks since this year’s watercress scheme post, but these pictures were taken a week ago.)

So how has it worked out so far?

Well after about 2 1/2 weeks I was quite discouraged as the filamentous algae was blooming while the cress was still looking as if it was still in transplant shock. Duckweed had also popped up and it seemed like this experiment would be over before it started.

My best guess was that the very clear water (from mist nozzle spraying cool clear well water into it 24/7) and direct sun were feeding the algae’s exponential growth at the same time the sun was stressing the cress.

I remembered that I still had a 4’x4′ frame that held two shade cloth panels from a summer lettuce experiment a while back. Conveniently, it fit over the watercress pool/bed/paddy perfectly so I set it up and waited to see if it helped.

Boy, did it help. The shade tempered the algae growth and encouraged the watercress growth, which it turn began to provide more shade over the water which further impaired the algae. The only issue was that duckweek seemed to prefer the shade so it grew a lot faster as well.

This is what the cress looked like a week ago, and the last week has brought notable improvement in the amount of cress (it has doubled). You can see the mist nozzle in the top picture; it has a high enough flow rate to run enough fresh water though the bed to keep it crystal clear and as well as keep the larger lower patty full of rice filled. (Seeing as how the rice paddy was also used as a frog orgy host, I have been more conscious of keeping the water level up for the tadpoles. )

I snipped off the tops of the cress in a small section (maybe a little over 1 square foot) and it provided much more that I expected. To separate the duckweed I ran cool well water over the cut cress and agitated it enough that the duckweed came to the surface and floated over the edge of the tupperware.

Verdict?

Delicious, and this small plot is likely more than enough to provide us what we need this year.

By the way, the “weed” grass growing in the pictures is actually volunteer rice from last year’s rice harvest.