Agriculture Reference
In-Depth Information
Once you get the brix above a certain number, which varies for different plants but is
often around 12, plant predators will diminish or go away completely. In general, they
won't be able to eat or even sense the plant as food. It's too healthy for them. At this
point, your food is a powerhouse of nutrition. We call it nutrient-dense. Imagine eating an
apple that has many times more nutrients than an apple you buy at a store.
Dr. Carey Reams is credited with doing much of the original research in discovering
that high brix means high quality, and he also determined necessary brix levels for many
different foods. He is reported to have entered the same watermelon in a contest three
years in a row to show how long food can stay good if it has a high brix reading.
We measure brix with a refractometer, a decent model costing about $100. Some say
it's the most important tool of the serious food grower. I get all of my instruments like this
from Pike Agri-Labs, and there are other good merchants around too. You don't have to
rush out and buy one now, but as you get more into growing, it's worthwhile.
I have even taken my refractometer to the local market to test food before I buy it. Rex
Harrill on his brix website points out that If you do this, be respectful of the vendors and
offer to buy a sample before you test it.
Gardeners can use brix to see if the food we are growing is getting healthier over time.
Like a soil pH test, it doesn't tell us much more than that.
The second reason we may want to test brix is more practical and useful. We can meas-
ure the brix in a leaf or especially a fruit from one of our plants, for example a tomato.
Note that a “fruit” is just the reproductive part of a plant, so botanically speaking, many
foods we call vegetables are fruits, such as tomatoes, pumpkins and avocados. So we test
the brix, then foliar feed that tomato plant, wait 30-60 minutes, and measure the brix
again. If the brix has gone up at least a couple of points relative to a control plant that we
also test, the tomato liked that fertilizer and we should spray the whole crop. If it stayed
the same or even went down, the tomato might not want that fertilizer today. Even good
organic fertilizers are sometimes not wanted by our plants.
This is an advanced technique that takes some practice. It isn't as useful for home
gardeners growing many different kinds of vegetables in their garden with just a few of
plants of each variety because it might not be worth the time to test, say, one tomato plant
in order to spray the other three. Or maybe it would. If you're trying to grow the best to-
matoes and you want to get many dozens of tomatoes from each plant, it could be worth
it. If you have a huge bed of something like potatoes, go for it.
For many plants, you need a reading of 12 brix in all parts of the plant, so if you're still
getting plant predator damage above 12 brix in the fruit, test the leaves. They may be the
weak link. Other plants need even higher brix. You also need to make sure you measure
from the same place on both the test and control plants. A series of cloudy days will bring
down the brix. Too much nitrogen or potassium will bring down the brix. A hot, dry,
