Pruning Basil

 This will be a post-in-progress for a little bit.  I am currently sprouting two basil plants for a pruning comparison, just to show what a difference proper pruning can make.  However, in the meantime, I can show the basil trimming basics.

Before we begin, an important Don't.  Don't pick individual leaves from a basil plant! Your plant requires leaves to produce the sugars and energy it needs from photosynthesis, and since you will be taking the tips, it needs the older leaves left in place.  The exception to this, is if the older leaves are sufficiently large that they are overshading the rest of the foliage; you can remove them in that case, but make sure there is other foliage.  You should never take it down to nothing but stem or only stems and immature buds.  If you are wanting periodic small harvests, just let the tips grow larger than buds before removing them; you can take up to ⅓ of the plant at any one time without trouble, but that doesn't mean it has to be for each branch; so, once you have two branches, you can let them get to 5 or 6 nodes long and then cut down to 2 on one branch if you leave the other intact for a while longer, and so on.

Like all trimming, the best method is to use a sharp, sterilized set of scissors or shears.  I personally use embroidery scissors, because the tips are needle-like and narrow enough to fit into the tiny little spaces needed for herbs, and are very sharp all the way to the tips.  That said, I'd be lying if I said I didn't just use my fingernails as often as not.

When is the proper time to trim basil?

One of the biggest mistakes people make with an herb garden, especially their first, is waiting too long to trim the basil.  This is of particular importance in an AeroGarden, because basil grows faster than any of the other herbs commonly grown in them besides dill, so it is important to keep it growing as compactly as possible.

Most people looking at this tiny basil plant, only about an inch and a half tall, think it's still much too small to trim.  Not so!  Even though it's still a baby, it has three distinct nodes with leaf pairs in addition to the cotyledons, as seen here:

Each leaf node consists of a pair, or two, leaves on alternate sides of the plant, and is positioned in the opposite direction from the pair below it.  So, if pair 1 were pointing north and south, pair 2 points east and west, and pair 3 again points north and south.

The first pruning for this little guy, is to simply reach into the crook between the leaves of node 2, and snip the stem just below node 3.

 

As you can see, it doesn't significantly affect the overall size of the sprout, since pair 3 were still barely more than buds.  However, because it removes the terminal growth bud, it forces the plant to change focus of growth.  In spiral growers like dill and parsley, if you remove the growth tip, it will frequently just die, or at least not put out any new growth.  However, in branching growers like basil, it will put out two new branches at the remaining leaf nodes.  You can already see the baby buds at node 1, which will become new branches now that the terminal growth bud has been removed.

Once the new branches grow out, you treat them exactly the same way — when they reach three leaf pairs, you remove the third one, leaving 2 behind, which will in turn put out 2-4 more side branches.

 

What if I waited too long?

Don't despair!  Basil is an incredibly hardy plant, that will make it through almost any trim as long as you leave it some mature leaves.  I have literally taken an overgrown single-stalk basil with around 20 or more nodes, and cut it down to 3, then had it bounce back into a big, beautiful basil bush with proper pruning from there on out.  

Dealing with Flowering

Inevitably in the life of any basil, it will eventually decide it's time to flower.  Unlike plants like lettuce, that completely change the way the plant functions, known as bolting, the beginning of the flowering phase in basil does not mean the end of its useful lifespan.  However, if left to simply flower, it will affect the flavor of the leaves on the plant, as the nutrients are diverted from the leaves to the flowers; some plants may simply lose flavor, while others may take on a faintly bitter flavor that some describe as 'soapy'.  

What this means, taken together, is that you simply need to be stringent about removing flower buds as soon as you can identify them as such.  At first, they will likely have to get most of the way to flowering before you'll be able to recognize them, and that's fine.  You may lose a little flavor from the leaves, but it should still be able to keep them from becoming unusable.  As you get used to your plants, however, you will eventually reach the point that you can recognize flower buds almost as soon as they form: the shape of a flower bud is distinct from that of a leaf bud.  A leaf bud will be roughly oval in shape, while flower buds have more of a square shape.

 

 

 

As soon as you are able to identify a flower bud, simply pinch it off.  You will want to go down under the leaf pair just below it as well, as there will often end up a bud just under them as well as above.  If you do miss a bud below the leaf pair, don't worry, just remove it as soon as you see it.

 

* More is to come, both updates to this plant as the side branches grow out, and a comparative experiment currently sprouting, to illustrate the importance of proper pruning.

For a general summary of herb pruning practices, see my post Pruning Herbs Overview.