Harvesting Garlic

As harvest time approaches, I always find it is a good idea to review my garden journals and see what methods I can improve upon this year.  Even for experienced growers, choosing the time of harvest can be tricky to get right.  Turbans are the first garlic I lift, and invariably, I'll be too eager to dig up those first bulbs.  Or, I'll forget that they might have been ready last week, rush out once I've looked at the notes from last year, and find that they wont be ready yet for another week.  There really is a window of only a few days in which to harvest with perfect success, so you have to be very watchful within that late July time period.

  How do you choose the right time?  The leaves are a perfect indication. As energy moves to the bulb, the leaves loose that expensive biological molecule, chlorophyll, and turn yellow. The leaves also loose moisture and other nutrients, and begin to dry down.  I stick by a guideline of 50% dry and yellowing leaves, and 50% of leaves that are still green. It will look more like 40% yellow/brown to 60% green in the field, because the drying leaves loose volume and visual presence.  A good way is to count the leaves.  A large bulb may have 8- 10 leaves, and be ready to dig when 3- 4 of those leaves are dry, and one is yellowing.  When in doubt, err on the green side of 50-50; that way you'll ensure that you have enough bulb wrappers to clean off, without stripping the bulb. 

Freshly dug Porcelain garlic.

   Each leaf is the out-grown portion of one bulb wrapper, and the wrappers start to decay as they dry down, especially in moist or wet soil.  Therefore, the number of green leaves on the plant at harvest time is a reasonable indication of how many wrappers will be left after cleaning.  The actual time of harvest can vary quite a bit, year-to year, depending on weather patterns.  2012 was warm early in spring and dry through the summer, so our garlic harvest was two weeks early that year.  In contrast, 2014 was at least a week late, due to a slow start in spring, and a cool summer with adequate moisture (sometimes more like aquatic moisture). I estimate that our 2015 harvest may be similarly late, based on the time of the scape maturity of each variety. Compared to last year, they are quite close in timing.

 Another  factor effecting the time of harvest is the size of the plants/bulbs.  Small plants have fewer leaves, and will be ready a little sooner than large bulbs of the same strain.

  Dig too soon, and the bulb will not be well developed, and may have a decreased storage potential. Remember, the cloves fill out right at the end of growth. As an experiment, try digging just one bulb when everything is still green, and slice horizontally through the bottom off the bulb. You'll see small, under-sized buds of developing cloves nestled within lots of thick, succulent layers of wrapping, even on a full-size, otherwise ordinary plant. The drying down process is an indication that the energy of the plant is returning to the bulb, and cloves, and you do not want to interrupt this process until the balance is just right. Certain varieties do develop cloves faster, and will have firm, filled-out cloves even when all the leaves are still green, (mainly Turbans). I suspect that others, including Marbled Purple Stripes, and possibly the later types, tend to have slow bulb development, and cannot afford to be rushed.  

  However, if you dig too late, the wrappers start to split, and the keeping quality is past its peak. As soon as the wrapped cloves are exposed to air, you have roughly one or two months to use them up. 
  Dig when the whole plant is dry, and you won't have to peel the cloves, but you may have to wash them. The bulbs will have started to open to the soil, with the bare cloves pushing out from the center like the opening petals of a flower. They do this in preparation for next season's growth, giving each other as much space as they can, as they individuate from the parent bulb. They'll have very little storage value at this point. 
  If this makes it sound too hard to grow garlic, don't worry, harvesting nice bulbs it is not that difficult if you check the garlic plot regularly during that critical time frame.  Also, garlic bulbs for the home gardener can afford to be "creatively appealing", and still receive a warm welcome into the kitchen.  The best way to get a feeling for garlic harvest is simply to do it.  Your own experience is very valuable, as each gardener's system, and each variety, growing in a specific type of soil, will have subtle nuances of variability.

Each garlic strain likes to live in it's own special time, but many of the strains that belong to one variety will have matching clocks, and be ready to harvest at the same time. Here is a basic guide:
Turban - June 25 - July 10.  Dig a little sooner than the 50-50 guide, as the wrappers split open easily and the cloves are developed early anyway.
Asiatic  - July 1 - July 15.
Artichoke - July 10 - July 20.  As a softneck, some of the plants may also fall over, like onions do, just before you'll want to dig them - this is another indicator of harvest time.
Creole - July 10 - July 20.  I expect that in more Mediterranean climates, harvest would be later, owing to a larger bulb size.  Few Creoles grow really well in Ontario, but they are so beautiful, and keep so well.
Rocambole - July 10 - July 30.  These you have to be especially careful with, because the bulb wrappers won't take extra moisture at senescence.  Some strains can be a lot later than others.
Purple Stripe - July 10 - July 25.
Glazed Purple Stripe - July 15 - July 25.
Porcelain  - July 15 - August 1. These I find are pretty durable in moist soils, and the wrappers don't split open too quickly.
Marbled Purple Stripe - July 20 - August 5. Wet weather can be disastrous for this variety, as the necks are susceptible to rotting. You may want to salvage them early, if you see a problem developing. 
Silver Skin -  August 1 - August 25.  Smaller bulbs may be earlier. This is a softneck type, and some of the plants may fall over close to harvest.

This is the unit we use to undercut the garlic. The red attachment has heavy blades
that slice through the soil below the bulbs, followed by steel fingers that lift and loosen.
If we get good, dry weather afterwards, we can leave the garlic like this for about three days
 before pulling it up and drying it in the barn. This can be accomplished on a small scale
 using a shovel, and just popping the soil under the bulb. Leave the bulb underground,
 otherwise the cloves will get green tips from the sun, and may heat up more than is
healthy for them. The ground acts as an insulator from light and heat, and allows us to
 vent off a little of the moisture from the plant, before it all goes inside.  

 The leaves on this Romanian Red garlic have turned mostly yellow
because they were undercut a few days before this picture was taken.
At this point I am pulling them up, cleaning them by rubbing off the dirt,
 and gathering them up to finish curing in the barn.
This is not how the plant should look if it were fresh dug,
and just being harvested.  The only reason the leaves are
 as yellow as they are, is because the roots were broken at the time
of undercutting, and that induced the plant to dry down more rapidly. Yo do have to be careful letting them sit like this, because if it does rain, and you haven't gotten them pulled up, all the water sits in the space you've just opened up with the undercutter, and the roots will be all sticky and wet, and harder to clean up.