Wednesday, August 15, 2018

Growing Onions at Harmony Valley Farm

By Farmer Richard

We have long felt that onions, and the related families of garlic and ramps, are essential to good health and should be eaten daily.  Thus, we consider onions to be a staple vegetable and plan to include some type of onion/garlic selection in every box throughout the course of our CSA season.  This is quite a feat, but we’ve been able to include some perennial and foraged crops such as chives and ramps that allow us to get our weekly onion selection until our overwintered scallions are ready. We plant onion sets and onion tops in the fall for our Egyptian walking onions and potato onions.  These are both multiplier onions that are established in the fall, continue their growth cycle the following spring and are ready for harvest ahead of any spring planted onions.   Next are the first spring scallions which are planted into the field in April from transplants we grow from seed in our greenhouses.  Once we’ve moved through the scallions, we continue with our seasonal progression and harvest an early fresh purple cipollini onion called Desert Sunrise.  This usually brings us to about the end of June when some of our early sweet Spanish onions are big enough to harvest.  Due to their high sugar content, they are an excellent choice for eating fresh as they are pretty mild.  Unfortunately, they don’t store very well.  That’s ok though, because they come in ahead of our storage onions and fill the mid-season slot very nicely.  Once we’ve moved through the sweeter Spanish type onions, we turn to our red and yellow storage onions to take us through the latter part of the season and through the winter.  Yes, it’s a challenge to pull this off, but if you look back over this year and previous years, you’ll find that we’re able to achieve this lofty goal most of the time!

We eat a lot of onions in our household, using them at least once a day if not more.  They often provide the background flavor base for our meals and we include them in everything from our scrambled eggs in the morning to soup, salads, etc.  We do believe onions play an important role in health and value our daily dose of nutrients from this food.  Onions contain powerful antioxidants, many of which are sulfur compounds.  These antioxidants play a role in overall health and immunity and benefit the body with their anti-microbial and anti-inflammatory properties.  They are also thought to play a role in cancer prevention as well as a whole host of other health benefits.  Eating onions raw may be slightly better than cooked, but onions in any form are beneficial.

Onions starting life in the greenhouse this March.
There are some challenges to growing onions, but I’m always up for a good farming challenge!  We start onions and shallots from seed in the greenhouse late in February.  We plan to take care of them for at least 7-8 weeks before they are transplanted into the field.  They are the first crop transplanted in early April.  They can survive snow and cold to 20° F!  While we don’t have to worry about weed pressure in the greenhouse, we are thinking about how to control weeds in the field.  Because of their slim, round stem, onions are poor weed competitors.  Plants that have a wide leaf are able to shade the ground and deprive weeds of valuable sunlight.  Onions grow upright and their tops don’t provide much shade, thus weed control can be a challenge.  They are one of the first crops to need hand weeding and we have found we have to make this job a priority so we have a clean field before we divert our crew time to picking strawberries and peas.

Twenty years ago we planted our spring onion transplants into flat bare ground.  If we managed to keep the weeds out, they grew well.  However, we faced another challenge presented by a tiny little insect called an onion thrip.  This little creature pierced small holes deep in the center growth point of the plant where organic insecticides offered limited control and protection.  The onion thrip is very difficult even for conventional growers, so they have gone to using 100% systemic insecticides, mainly neonicotinoids that make every part of the plant toxic.  It works well to control the thrips, but do we want to eat a toxic plant?
Our onions grown in the flat ground would look good until we brought them into the greenhouse to dry.  After drying and cleaning, we found a soft rot in the neck and top of the onion and often a bad rotting ring somewhere in the onion.  We went to the extension service and had the disease identified by plant pathology and asked what we could do.  The answer was to grow on raised beds.  Heavy rain events on small onions make them vulnerable to getting bacteria inside the center of the onion.  The bacteria causes rot on the inside layers of the onion but appears to be fine from the exterior.  We only see the damage after some time in storage or when we cut them open to use them!  The same is true with another onion disease called neck rot.  Bacteria enter the neck and develop during curing, and often go unnoticed until the end user cuts it open!  This all points back to thrip damage that created the entry point to allow the bacteria to enter!

Raised beds?  How do we do that?  This is not a garden.  We figured it out.  We built equipment to create a 6-8 inch raised bed with a smooth top to plant or transplant all our crops on.  Now, most of our crops, onions included, are planted on raised beds.  The raised bed allows excess water to run off the bed into the lower wheel track between beds and careful ditching at the lower ends of fields prevents the water saturation that would cause onions to later rot.  With this new system, the quality of our onions improved!  But we still had the onion thrips piercing holes that allowed disease bacteria to enter the neck.

Onion transplanting crew, putting the little onions in the
raised beds with the reflective plastic mulch.
Next, we found a reflective plastic mulch that we could use to cover the beds.  It is shiny like aluminum foil and when the sun shines on it the reflection off the mulch disorients thrips and totally deters them from entering the field and onion plants.  We found that this technique also works for other insects on other crops!  So we covered our raised bed with reflective plastic and the high and dry onions without the thrip damage were better than ever!

Did I mention that growing onions has some challenges?  The raised, plastic covered bed has 2 drip tapes buried under 4 rows of onions.  With the help of water sensors we found the onions need lots of water, sometimes we have to irrigate twice per week when it is hot.  Each time we water the onions, we can also give them some fertilizer through the drip lines to provide the nutrients and nitrogen they need to produce well.

The sum total of our efforts allows us to prevent thrip damage to produce healthy onions.  We do still need to manage the harvest and try to bring them in with some green still remaining in the tops. We put them into our shade covered greenhouses to allow them to dry down, cure and set skins for longterm storage.  We are now able to have disease free onions that produce yields comparable to conventional yields but without using systemic poison!

Last year's onions drying in the greenhouse.
Once the onions are dry, we choose to top and clean all our onions and shallots by hand.  It takes time, trimming the top off of every onion with a scissors, but we think it is worth it for a pristine appearance.  Mechanical means of topping onions can cause injury to the onion which then can limit their ability to store well.

As you can see, onions are very important at Harmony Valley Farm and we have a very good crop this year.  We plan to keep you supplied with onions weekly until our CSA delivery season ends.  If you get behind and they start building up on your counter, don’t worry. If you store them properly they will keep well for quite awhile.  Keep them in a cool, dry location out of direct sunlight.  When the season ends, we’ll give you an opportunity to order more onions, shallots and red cipollini onions to supply your pantry through the winter!  Display your onions proudly in your kitchen, eat them daily and enjoy being healthy.

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