Agriculture Reference
In-Depth Information
windy day may bring up the brix, giving you the impression that you're doing better than
you really are.
Other unknown factors seem to cause the brix to increase and decrease throughout the
year. The way to get brix up long term is through improving the health of the soil. Phos-
phate is especially correlated to brix, so if you get your phosphate availability consistently
up, your brix will go up.
I'm not going to get into the details of using a refractometer, as those instructions come
with the device, but it's really simple. Use a pair of pliers or a blender to get a little bit of
juice out of the fruit or leaves and place it on the glass plate. Look through the hole like
you would look through a kaleidoscope and you have your brix reading.
A refractometer can also tell you if you have enough calcium. A blurry line where the
upper and lower part of the scale join tells you calcium is sufficient. A sharp line indicates
deficiency. Not everyone agrees with this seemingly strange methodology, but I've found
it to hold true much of the time when compared to a soil test.
The second test to do is a plant sap pH. This isn't something I recommend most home
gardeners need to worry about, but it's interesting enough that I'll mention it here. For
some reason, the closer the pH of a plant's sap is to 6.4, the healthier that plant will be, re-
gardless of the species of plant.
If the sap pH is above 6.4, there's a good chance there is a shortage of the anions nitro-
gen, phosphate and/or sulfur. The plant is also likely to be found as food by insects. The
higher the pH, the worse the problem. At a sap pH of 8, you will definitely have insect
trouble.
If sap pH is below 6.4, there's a good chance you have a shortage or imbalance of the
cations: calcium, magnesium, potassium and/or sodium. The plant is likely to be found as
food by diseases. At a pH of 4.5, you will definitely have disease trouble. As we'll see,
baking soda can help curb fungal diseases, perhaps simply by raising the leaf surface pH.
Also, the further the sap gets from 6.4 in either direction, the poorer the quality, taste and
storage life food will have. I have read that our urine and saliva should be close to 6.4,
too.
The reason I don't suggest home gardeners do the sap pH test is because you need to
spend a couple hundred dollars on a special pH meter, and when you've determined your
plant sap pH, you're not really much closer to knowing which nutrients are deficient. As
such, this test is mostly used to see if your management practices are moving your plants
towards better health.
