Field Day: Media Trial

Field Day: Growth Rate

Field day: Germination

Field day!

Yesterday 92 people crammed into the greenhouses to hear about salad greens.

92!

Over the next few days I'll be posting the material from the field day.  It will all be easily searchable by clicking on the new Field Day icon in the right hand sidebar.

Field Day: Variety Trial

What is a 'baby' sized green?

There is no standard size to define what is considered a 'baby' sized salad green - at least I haven't seen one yet.  So I made up my own set of parameters based on observation, salad eating and a few reliable sources.  Johnny's Select Seeds suggests harvesting salad greens at 4-5 inches tall  which translates to 10.16- 12.7cm.  I feel like Eliot Coleman of Four Season's Farm wrote that he harvests salad greens at 4 inches, but since I can't find that anywhere in my notes I could be wrong.

For harvesting and data analysis I consider lettuce and brassicas in the 8-12cm range a good size for baby greens.

Currently, I consider 6-10cm perfect size for spinach.  Unlike lettuce and brassicas, spinach has an official size: the size of a soup-spoon (again I can't find my notes on this right now).  I don't have real soup spoons, but hopefully a tablespoon is an ok substitute.

Field day preparations

I've spent the last few days preparing for the field day, which is only five days away!  The posters are made, and all that's left is cleaning up the greenhouses.  Happily, they survived the heavy, wet snowstorm on Tuesday.

Now that daylight lasts all the way till 7pm greens are growing quickly.  Sometimes as much as a centimeter a day!

Cut-and-come-again greens

Nearly all the greens I grow are considered cut-and-come-again greens.  But what does that mean? And why haven't I ever mentioned it before?  First think about how salad greens grow: new leaves come from the growing point, which is at the bottom of the plant.  If you don't cut off the growing point when harvesting, new leaves will emerge and you can harvest a second time!

Brassicas, like the kale and mizuna above, make really good cut-and-come-again greens.  They are fast growing and often have jagged leaves that hide any past scissor marks.  Leaf lettuce is not quite as good as a cut and come again green because it is slower growing and because it doesn't hide past harvest cuts well.  In the right hand picture below you can see a very flat-topped lettuce leaf that wouldn't look so nice in a salad.

Spinach is a good cut-and-come-again crop because it's leaves are on longish stems.  Spinach is slow growing, so plants grown on benches, in flats may run out of nutrients before they are big enough to be harvested a second time.  

A second harvest from greens offers the chance to have additional salad greens without much extra labor or materials.  This spring I'm going to asses the regrowth on greens to answer these questions:

• How do regrowth yields compare to first harvest yields?
• Does the quality of the regrown greens change?
• Are some greens better suited than others for regrowth in a bench-top system?

Vates Kale

I planted this kale a month ago and forgot what it was because I didn't label the tray.  I thought it was broccoli for a few days (even though I don't actually have any broccoli seeds). But it's not - it's Vates kale from High Mowing.  It's delightful and sweet and better than red russian kale.  The hairs on the edges of the leaves are not sharp.  If I didn't have to spray it with aphid killing pesticides I would be eating this weekend.  Oh well, it will be eaten soon.

Attack on the Aphids

There were so many aphids in the greenhouse it was almost embarrassing.  Remember the pictures of leaves covered in aphids?  It was about time I did something to stop them. 

Goodbye greens!  This cart full of plants contained the very worst of the aphids.  So they got thrown out in the blue dumpster.  (Usually I compost everything, but the road to the compost pile is too mushy to drive on right now.)

Luckily the aphid infestation is in the non-organic certified greenhouse.  So, we sprayed two types of pesticide (by 'we' I mean the farm manager did the spraying).  The cocktail contained one part Botanigaurd and one part Azatin.  

BotaniGaurd is a mycoinsecticide, meaning spores adhere to the host and produce enzymes that dissolve the hosts cuticle.  

Azatin is an insect growth regulator.  When an aphid (and many other insects, fish and aquatic invertibrates) comes in contact with the pesticide it interferes with with the organisms ability to molt, thus killing it.  This is a pretty typical kind of pesticide.

Next week I'll release two beneficial insects: ladybugs and parasitic wasps.  They will control the aphids on a long term basis.  (The picture above is neither of these.  It's just an ordinary wasp on goldenrod.  I don't take many insect pictures.)  I'll write about them in detail next week when they get released.

Attack of the aphids

Last week I announced that there are aphids in the greenhouse.  By now there are more, lots more and we have begun a three-pronged attack on them.  But first, it's important to know just who we are dealing with.

The foxglove aphid, Aulacorthum solani, has a huge range of host plants and can transmit 45 diseases, so it's pretty bad.  The adult aphids are 1.5-3 mm long and are dull green or brown.  Their antenna are longer than their body and have dark joints.  Their legs also have dark joints and their cornicles are dark at the ends.  The picture below (which I did not take) shows all these characteristics really well. 

Photo taken by Andrew Jensen (aka Aphidman)

They like to colonize deep in plants on tender, young leaves.  I definitely found this to be true.  See how gross the young spinach leaves look?  What really kept me up at night is the reproductive rate of these aphids.  In just THREE DAYS the population doubles in a 55 degree environment.  How could I sleep when I knew aphids were busy multiplying that fast?  Happily, we've started attacking the problem.  You can look forwards to the next installment of "Attack of the aphids."

Sources: AphidID, Jandricic et al., 2010, RIS

Morning light

We had three sunny days in a row.  

Sunglasses were pulled out, sunscreen was applied and 

greens started growing like crazy.

wintergreens media trial

Now that it's March and the days are getting longer the greens are growing really fast.  The benches are filling up and I am eating lots of salad.

I looked back at my original fall plan for wintergreens and realized I never once wrote about the media trial I outlined!  This trial ran successfully in the fall, so I'm doing it again to see if I get the same results in the spring.  

It's a pretty simple experiment: there are five media types in which I grow mizuna, lettuce and spinach.  I measure leaf length and harvest yield while the greens grow and use that data to compare growth rate at the end. 

Looking at the overhead shots of each green in each media type you get a pretty good idea of the results.  The pictures were all taken on the 4th of March when the greens were 26 days old.  The two composts and peat with osmocote fertilizer have very similar growth.   Sustane is an organic fertilizer (you can tell, it smells like chickens) but it doesn't do so well in this setting.  Sungro is the name of the peat I use.  It doesn't have any fertility in it and demonstrates pretty well that greens need nutrients to grow!

Winter Greens Field Day!

Are you interested in growing salad greens during the winter? 

Have you ever wanted to see what I'm doing? 

Do you have a burning desire to see tokyo bekana up close?

Now is your chance!

The Winter Greens Field Day will be held on 
Tuesday, March 26 from 3-5pm at Woodman Farm.  

Everyone is invited to hear about my salad greens research trials and share what you're doing.  

Click here for the offcial announcement and more details. 
We ask that people RSVP so we know how many to expect.

Have questions?  Let me know!

Aphids in the greenhouse

Aphids are a common problem, so it was just a matter of time before some wondered onto my greens.  At least that's what I'm telling myself now that I've found some lots.  Aphids are in the Homoptera order of the insect family.  Their distinguishing characteristic are two exhaust pipes, called cornicles, on their butts that secrete a warning scent when they are being attacked.  My camera is not powerful enough to take a picture of the cornicles, but you can see them here. 

What I'm eating today: birthday cupcakes

The cupcakes I made for my birthday this weekend needed some decoration.  

Tiny spinach and mizuna leaves looked pretty cute, if only for a few hours.

Photo friday: spinach germination

The past few days have felt like we have turned the corner towards spring.  Birds are out, the ground is muddy and there are buckets on the sugar maples.