One Way to Increase Yields Up to 50%
There are quite a few ways to significantly increase the amount of food that you can harvest from a small garden. I describe ten of them in my free course. But I now have another one:
Start your transplants in larger containers – give them double or triple the amount of soil that they usually grow in. Then plant them into your garden long before they even have a chance to think about becoming root bound.
This helps in a couple of ways:
1) Larger containers maintain a more even moisture level between watering, which helps your plants to grow more quickly and vigorously.
2) Larger containers will let your seedlings reach transplant size well before their roots start to feel constrained by the size of the container.
Many gardeners and nurseries grow their cabbage-family transplants in small containers, such as 1.5″ to 2″ wide. I have, too. But I just found out this year how badly that can affect my plants throughout their entire lifespan. They don't have to actually become root bound in order to have their potential growth stunted.
My sister and I started about 130 broccoli and kale plants for our early spring garden in 2014. We had a motley collection of containers to use, of different sizes and shapes. So, this was a perfect way to discover just how much using different size pots can affect plant growth and final yields.
The pots on the right side hold about 2.5 times the amount of potting soil than the smaller pots on the left. You can clearly see how much larger the plants are on the right side – even allowing for taller containers. Both sets of plants were started at the same time, and given the same soil and growing conditions.
While some vegetables produce small, slowly-growing seedlings that do just fine in small pots, most crops in the cabbage family (including broccoli, kale, tatsoi, etc) really thrive best if they are given a bit more soil and elbow room. You CAN grow these seedlings in small pots. Don't think you can't! But your plants will grow larger and faster, and produce more, when given bigger containers.
You can still clearly see the difference in the size of my kale, even after they have been growing in the same garden bed for several weeks!
The kale from the larger pots have almost completely filled their part of the garden bed, but the kale from the smaller pots still have a lot of empty space between the plants. All of these plants were spaced the same distance apart and treated the same way. Just slightly stunting your plants when they are young can have a life-long effect on their growth!
When it came time to harvest the kale, the plants from the larger pots were still 3 inches taller, and had more leaves. The smaller plants never caught up in size. And here's the biggest difference in my bottom line:
When it came time to harvest and freeze the kale, the kale plants that were started in larger pots produced 50% more kale leaves by weight! I measured this by what we were actually able to put in the freezer, with the stems and stalks removed.
All of the plants were started and transplanted at the same time, and given the same soil and growing conditions. The only difference was the size of their containers.
Giving my young plants over twice as much soil to grow in when starting them as transplants encouraged incredibly vigorous growth that carried through their entire lifespan. Small pots stunted the young plants, and they were never able to catch up. As full-grown plants, they all looked just great, but there was a significant difference in their full-grown size.
Mind you, the “stunted” plants didn't look stunted! They were as large as most transplants sold in nurseries. Their containers actually had more soil than many nursery-sold transplants have. And they were NOT root-bound, either. Most gardeners would have been thrilled with the size that these plants eventually reached – but they didn't reach their full potential.
So, if you want the maximum harvest from your garden, it's worth experimenting with larger pots for your transplants. So far, the best size for my cabbage-family plants seems to be about 3″ wide square pots, that are about 4″ deep. This holds 2.5 times more soil than smaller round 3″ wide by 3″ deep pots.