Saturday, May 12, 2018

Growing Lettuce Indoors, Easier Than The "Easiest" Way


I was brimming over with enthusiasm when I wrote this post about indoor gardening; specifically, how to grow lettuce indoors. Living where we live, lettuce has a very short growing season either side of the year and absolutely cannot be grown in the hot summer without instantly turning bitter. Also, the sandy soil refuses to stay moist unless I water two to three times a day (or we have a decent rainfall every other day). 

So I started growing lettuce inside as described in the post linked above, with net cups containing coconut coir and the lettuce plants sitting on top of a bed of pea gravel in a plastic cup.
See the plant roots coming out the holes in the net cup as I hold it above the larger plastic cup. The dead leaf is normal, as I've harvested from that plant numerous times (in other words, it's old).

The pea gravel in the larger plastic cup, on which the net cup sits.

This method definitely works, but I found as the plants grew larger that I was spending more time than I wanted watering them. Instead of just watering once or twice a week (on one video I watched of a similar method of indoor lettuce gardening, the gardener said she only had to water once a week - ??), I was watering them every second to third day. It’s tricky to pour water in between a net cup and a plastic cup, and it was even trickier to do with the lettuce on the top shelf.

So my enthusiasm for growing lettuce indoors began to wane quickly. It all but disappeared the first day I had to clean out the plastic cups when the first batch of lettuce started to bolt. It took me thirty-five minutes to clean out twelve of them, including pulling the lettuce with its roots out of the net cups and rinsing off the pea gravel (which you’re supposed to do to get rid of any algae that has grown).

I’m sorry, but I have better things to do with both my time and with water – a precious resource in any event, but even more precious to us because we are off the water grid. No well; we collect rainwater in three rain tanks, two rain barrels, and a small pool.

What happened next?

I decided there had to be an easier way to grow lettuce inside. I noticed that when I start lettuce seedlings in the net cups on a plant saucer, they would grow roots out well before I placed them in their final home and did just fine. 

Also, I knew that with lettuce, as long as you allow some of the roots to have access to air, the plants won’t drown and the roots won’t rot. 
 
My solution? 

Skip the middle man!

The plants in net cups do just fine sitting in water. So why complicate it?

Here’s what I’m doing now:
Lettuce in net cup sitting right in water at bottom of plastic box. Weird thing on the left is a rotted leaf from next plant over.

Lifting up a net cup so you can see it better.

Yep. The net cups sit at the bottom of a plastic storage tub, and I keep between a quarter and a half inch of nutrient solution (water with hydroponic fertilizer mixed in) at the bottom of the tub. It takes hardly any time to add more water, because I’m just pouring once. I don’t have to fight with cups and net cups. 

As you can see, the lettuce is doing just beautifully.

And, of course, I won’t have to ever wash any more pea gravel ever again!

Two disadvantages

So far, I’ve discovered two disadvantages to this method. First, the net cups being light weight and the lettuce plants causing them to be top-heavy, they are prone to tip over. You have to check them at least every other day and make sure all the cups and plants are upright. Otherwise, you’ll end up with rotting leaves.

Speaking of rotting leaves…since the cups are so close to the water, some of the leaves will grow down and get wet. And, yes, rot. But I think these two disadvantages outweigh the work the dual cup method requires.

Oh, one more thing: I’ve got a mostly-full bag of pea gravel for sale… ;)