Germination trials or an overview of Experiment Number One

The first thing we are going to be looking at are seed germination rates in different low tunnel treatments within the greenhouse.  The goal is to create a low tunnel that will significantly decrease the time it takes for seeds to germinate.  In cold weather seed germination can sometimes be a limiting factor in plant growth.  For example, lettuce will germinate best around 68 degrees Fahrenheit, but will happily grow at much lower temperatures.

Here's an overview of what is going to happen:

The six low tunnel treatments

1. Clear plastic - the thick stuff used to cover greenhouses
2. White plastic 
3. Clear plastic with holes - a light weight plastic with holes that allow for ventilation
4. Floating row cover - often called 'remay' on farms
5. Heat mats - to provide bottom soil heat
6. Control - just plants in the greenhouse

The three varieties of greens

• Spinach - the slow germinator
• Lettuce - the mid-rate germinator
• Mizuna - the fast germinator

Why only these three greens?  To properly conduct a Scientific Experiment there have to be lots of replications.  For instance, if we do six replications of 24 plants per treatment that ends up being almost 2000 seedlings to plant and count for each species of green.  To keep the counting low-ish we picked three greens that represent a range of germination from fast to slow.

An abridged protocol

1. Finish building the low tunnels.  This involves drilling into metal using tech screws.  I am not good at this and have been putting it off.
2. Plant a lot of seeds.  They haven't arrived yet which is why I can put off the drilling.
3. Count the number of seeds that have germinated every day for ten days.  

That's it!  I'll be writing about the process and results as they unfold with plenty of pictures.

Greenhouse or tunnel?

High tunnel

looks like a typical greenhouse but is not heated.

Greenhouse

has a source of heat like propane.

Low tunnels

temporary structures that look like mini-greenhouses.  

Sides are held down with sand bags or dirt and have to be uncovered for harvesting.

plant profile: Mizuna

Brassica rapa juncea

(kyona, shui cai)

Appearance - Mizuna is an upright green with deeply cut serrated leaves on thin white stalks.  It is part of the hot and spicy group of mustards in the Brassica rapa family but has a mild flavor.  It can tolerate both heat, humidity and cold weather making it a good year round crop.  

Uses - Originally, mizuna is from China but is thought of as a Japanese green that is primarily used for cooking.  Here in the west is mainly used as a salad green but as it becomes more well known its uses are growing to include stir fries and stuffing for raviolis.

Varieties

Culture - Mizuna is easy to grow and should be treated like other Brassicas.  Sow seeds 1/4 inch deep in moderate temperatures between 60-85.  Once the seeds have sprouted temperatures a bit lower, between 55-75 degrees, is sufficient for growth.  

For baby greens seeds should be sown in 2-4 inch bands with 60 seeds per foot.  For larger leaves sow only 15 seeds per foot in 2 inch wide bands in rows 18 inches apart.

Harvest - Baby greens should be ready for harvest in about 21 days, depending on temperature and light levels.  Full sized leaves should be harvestable in 40 days.  Mizuna is a cut-and-come-again crop and will produce multiple harvests.

Pests - Like all Brassicas flee beetles are the major pest of mizuna.  Using floating row covers is an easy method of controlling these pests.  For more information check out the UNH Cooperative extension's page on flee beetles.

Wednesday quiz: how do you like your lettuce?

why fall is a bad time to start vegetables

I am getting all excited about growing lettuces and new varieties of greens that I haven't seen before but now is just is not the time.  It is still warm enough out but the real issue is lack of light.  At this time of year - late fall - five o'clock comes around and it is dark as midnight.  This affects plants just as it affects people.   Less than ten hours of sunlight significantly decreases the amount of growing leafy greens will do.

These little spinach plants illustrate this idea.  They were planted over a month ago and have a nice warm growing space inside a cold frame but grow very slowly because day-length has been decreasing.  Combating this dilemma is simple but requires a bit of planning (or planting!) ahead.  Greens and some other vegetables planted in late August and early September will have had ample time to reach maturity by now and will continue to "hang out" in the garden for a long time even when days are short and the nights get chilly.

Kale is a perfect example of cool hardy vegetable that will live in the garden.  Just make sure you plant extra at then end of summer.   Most cool hardy vegetables can survive light frosts.  Further protection from cold frames and row covers can help stretch the season a bit longer.  Cooler temperatures increase sugar and nutrient levels in vegetable making them even tastier.

mesclun

Endive, lettuce, arugula and chervil from Johnny's Seed Co.

What is mesclun?  The traditional French mix included only endive, lettuce, arugula and chervil, but now it can include any number of baby greens harvested and mixed together.

plant profile: lettuce

Lactuca sativa

Asteraceae family 

Appearance

Uses

Varieties - There are hundreds of lettuce varieties but we'll only be using leaf lettuces - those that don't form heads. Leaf lettuce seeds can be purchased as a few pre-mixed varieties which are chosen to compliment each other.

Culture - Lettuce is a cool loving crop best grown between 60 and 65 degrees Fahrenheit, but can grow in temperatures as low as 40 degrees. For salad mix or baby-leaf size sow seeds in a 2-4 inch band with about 40 seeds per foot.  Cover lightly with soil and keep it moist.

Harvest

Pests

plant profile: spinach

Spinach is my favorite green.  


It is not fast growing like some of the brassicas.  Nor does it have sexy colored viens like swiss chard or red russian kale.  Harvesting spinach can be a true labor of love when each leaf has to be cut individually.  Despite all of this, spinach is great.  No, it's beyond great - it is one really cool plant.  Here's why:

~ Spinach is a diecious crop meaning there are male and female plants.  In the absence of any male pollen producing plants female flowers can ‘revert’ to become pollen-producing flowers, enabling continuation of the sexual reproduction cycle.  

~ Spinach is one of the hardiest leaf crops. It grows best in sandy, porous soil but can adapt to a wide range of soils.  Spinach germinates best in cool soil and can germinate at temperatures as low as 35 degrees Fahrenheit.  

~ Spinach can grow at very low temperatures.  Other leafy crops can tolerate the cold but will not grow.  Spinach grown in the cold has higher concentrations of nutrients like vitamin C as well as higher sugar levels.

building the low tunnels

We have two kinds of benches, wood sided and metal sides.  

The wood ones are way easier to drill into, but either way setting up hoops on them is pretty easy.  

We used:

9' long pieces of 1/2 inch PVC

metal brackets

tech screws or metal to wood screws

The bottom of each bench is covered with a layer of clear plastic since our goal is to build a sealed chamber.  The plastic is a bit brown because it had been used once in the field.  Next we covered each tunnel with a different kind of cloth or plastic to see what effect they would have on internal temperatures.  Each tunnel has a temperature sensor that measures temperature on the hour so all we have to do is sit back and wait.

the wintergreens project

This project is looking at the practicality of growing lettuces, asian greens and other lovely salad greens in UNH greenhouses during the next two winter seasons.


Producing high yields of cool-loving crops would be beneficial for everyone.  Consumer demand for local produce is increasing, especially in the winter.  Most farmers are unable to keep up with the winter demand and can be hesitant to experiment during the cold months when heating is expensive.   


Of course you can grow plants in greenhouses you say- that is the point of a greenhouse.  What we are going to be looking at is how to use greenhouses without adding much additional heat, no additional light and using materials commonly used on a farm.  


On this blog we will be tracking our trials and successes through the winter and spring.     

low tunnels in the greenhouse

Temperature values used are from H. C. Wien's paper
"Use of low tunnels to improve plant growth in high tunnels"

Today we started setting up germination chambers on top of the existing greenhouse benches.  Really our germination chambers are just fancy low tunnels.  Low tunnels are simple hoop structures made from wire or PVC and covered with permeable fabric or plastic.  Their benefits are two-fold for organic and small farmers, they keep insects off plants and warm up the air.  We plan on using the increased temperature to our benefit.

If you put these low tunnels inside a greenhouse or high tunnel (unheated greenhouse) plants are even more insulated from the outside cold.  Our first trials using this arrangement will be looking at the temperature ranges using different materials as covers for the low tunnels.  Permeable fabrics, plastic sheeting and permeable plastic all have their benefits and drawbacks.