Thursday, March 7, 2019

Eastern Bottlebrush Grass

Bottlebrush grass, Elymus hystrix, is a pretty common native species found in open shade and woodland edges in Maryland.  Its native range is from Maine to Georgia and westward to the Great Plains.   It is a cool season grass, meaning that it begins grows actively when soil temperatures are between 50 and 65 F.  Attractive seed heads are produced in June and these often persist into the fall.  Like most cool season grasses it shuts down in the heat of summer, but comes back to life in the fall, sometimes staying green all winter.  I am looking at using this grass to help fill in the woodland edges after removing the invasive Japanese stilt grass, Microstegium vimineum.  Ideally once it gets established it will grow up and shade the ground before the stiltgrass germinates later in the spring.

Eastern Bottlebrush Grass at the end of June growing along a trail near Harper's Ferry, WV

Rather than buying new seed, I harvested some from my existing plants last October and stored them dry in a refrigerator at about 42-45 F.  They were left there until I planted them in mid-February under lights.  Bottlebrush grass seeds do not require moist stratification to get them to germinate, just cold storage for a few months.

Since I have had less than stellar success with starting seeds I thought I would compare different ways of planting the seeds and see how well each germinated.  This was a limited study with only 8 seeds under each of 8 conditions.  All were planted in a soil-less seed starting mix and put on a warming pad to give a soil temperature between 65 and 70 F.  The long awns on the seeds, which give the brush effect, are not easily removed.  I pulled the awns off of each individual seed.  For these I planted one set vertically, and the next horizontally, each about a quarter inch deep.  The third set I planted vertically about a half inch down.  I repeated these conditions using seeds with the awn still attached.   

Here's the first leaf of Eastern Bottlebrush Grass.  The inital shoot has a reddish
 tinge that makes it harder to spot on the dark background. 
The last set of seeds were moved to a colder refrigerator for about a month.  I thought this might simulate winter conditions better.  One set of these I cleaned and planted horizontally, and the other was with the awn attached and planted vertically. 

Seeds began germinating after 9 days.  Rather than going into too many details the results indicated that seeds that were cleaned germinated more quickly, but after a month there was little difference between cleaned and uncleaned seeds.  Where I did see a difference was with colder storage.  Seeds stored in the back of the refrigerator germinated at half the rate of the others stored at about 44 F.  I suspect at the back of the frig, where the coldest air comes in, temperatures would sometimes drop below 32 F.

Now I have about 30 plugs of a native grass that I can grow on to use in my battle against stiltgrass.

Saturday, February 2, 2019

Garden Trellis

My vegetable gardening style is on the wild side.  I give maybe too much weight to reseeded native flowers over food producing plants.  I start out with grand expectations of neat rows, but inevitably weeding the garden becomes less important as other tasks loom.  In fact this year I got things nicely cleaned up with weeded and fertilized beds and mulched paths.  Unfortunately reality struck with a cool wet spring that offered few pleasant days to keep the garden neat and clean.

I got the garden all cleaned up in April of 2018 with great intensions
 for keeping it neat, but ...
One way to bring order to the garden is to add visual structural elements.  These add focal points or visual anchors that rise above the clutter.  In past years I've used fallen limbs to create tripods to support beans, cucumbers and tomatoes.  Since these were not well anchored, they end up falling over as the season wears on.  This year I decided to build some semi-permanent tripods that could be left standing for a couple of seasons and could be easily repaired if and when the time comes.

Schematic for my garden trellis.  Parts include 2x2 wooden legs, 3" diameter PVC pipe,
 6" wood square, some 2.5" deck screws and a bag of coarse sand.

I liked the idea of using tripods.  They are easy to build and structurally sound.  Here is a schematic plan that I came up with for my tripod trellises.  I wanted to build it out of 2 by 2 cedar, but it was not readily available in long lengths.  Being somewhat impatient I got 2 by 8 pressure treated boards that I ripped into 3 1.75" wide pieces about 7.5' long.  Before ripping into thirds, I cut off a 6" piece (actually 6" x 7.5") to make the top support.  I trimmed this rectangular piece into a hexagon on the band saw and angled 3 of the faces at 12° to match the angle of the tripod (see the diagram).

Completed intallation of tripod legs.  Having the PVC sleeve
 above the soil level helps keep the sand clean.
 Rather than driving the trellis directly into the ground, where constant contact with wet soil would accelerate rotting of the wood, I put in a length of 3" PVC drain pipe that I would later fill with sand to make well draining fill that would also hold the trellis firmly in place.  (Note that the thinner schedule 40 PVC drain pipe can be used rather than schedule 80, since you are just forming a soil barrier.)  To further improve the weatherability I also painted the lower 2 feet of the wood with a water seal coating. 

My biggest mistake last year was getting started too late in the season, after the garden had started growing. To put in the PVC liners in the established garden I used a trenching shovel (about 3" wide) to dig a fairly narrow hole in at a roughly 12° angle and 16-18" deep.  I then used the PVC tube itself to remove the last bits of the soil and get a firm fit.  The other two liners were put in 31" away from the first to form an equilateral triangle (see the diagram). 

The top support is attached to the legs
with 2.5" deck screws.  These are easily removed
 if I needed to replace one of the legs.
After the liners were in, it was time to position the legs of the tripod.  With the 3" lined holes there was sufficient wiggle room to get the legs to align.  The top hexagonal support was attached to the legs with 2.5" deck screws. The screws were prepositioned about 9" from the ends of the legs so that I only had to drill them into hexagonal support (into the angled faces).

The completed trellis, with a spiral of twine,
is ready to support these cucumbers.
With the top support attached and the legs in their PVC sleeves I filled in the space between the sleeves and legs with coarse sand.  First I put in about an inch of sand as a base under the legs then finished by back filling with sand to the top of the sleeve with occasional tapping to make sure the sand was evenly and firmly distributed. It took a little over a half cubic foot of sand to to do 4 tripods (12 holes).

Even with this late start I was able to train the tomatoes and cucumbers onto the trellises that I had built around them.

I tied some rubber balls to the blunt top ot the tripod using fishing line. 
The lightweight balls won't damage the plants if they fall off.

Now I am again getting ready for a clean start in the garden.
It's February and the trellis are ready to go.  Well, maybe in a couple of months.


Tuesday, January 8, 2019

What to do with old potting soil?

Here's about half of my potted plants that I do each spring.

I hate to throw out used potting soil.  I have about 30-40 pots in various sizes.  If I were to change out the soil every year I'm looking at buying 150-200 quarts of new soil each time.  Then I would also need to get rid of the used stuff.  In many cases potting soil can be reused for two or three seasons with a little refresher.   Here are three things you can do with used potting soil.

Here's whats left as the growing season ends.  These will all be brought in
under cover to avoid damaging the pots in freezing weather.

Rejuvenate it:  I've reused potting soil for several years.  It does degrade over time and will benefit from being rejuvenated.  The biggest problem is when it gets too dense and no longer drains well.  Can also make it more difficult for roots to grow and it gets soggy.  Old potting soil has also lost whatever fertilizers were there at the beginning, so nutrients will need to be added.  Espoma Flower- or Plant-tone are good organic choices.  Osmacote slow release fertilizer is another good choice, though not organic.  Compost is also a good form of fertilizer, but too much, any more than one third by volume, in the potting mix can decrease drainage and soil aeration.  Last year I tried using alfalfa pellets stirred into the container mix where I was growing tomatoes in pots.  It gave moderate results, but I think I needed to use a lot more or more frequent additions to get sustained results.  (The NPK value for alfalfa pellets is about 3-1-2.)  

To lighten up older potting soil you can mix in fresh peat moss or coir and/or pearlite.  To improve drainage some sand could also be added, but that ingredient does not get depleted from one year to the next.  I am torn about leaving old root balls in the container mix.  They slowly decompose to build organic matter, but they also are places where the soil is denser and they may harbor some plant pathogens.  I am tending to pull most of them out now and throw them into the compost pile.  Also pick out any bugs and weeds that you see.  I've seen warnings about not growing tomatoes in the same soil two years in a row.  This is due to root pathogens carring over from one year to the next.  That being said, I have replanted tomatoes in the same soil and they have survived, but I would recommend following the recommendation if your tomatoes have suffered any fungal disease.  If you believe your soil is infected with pathogens, or if it is loaded with weed seeds it can be pasteurized by warming it to 120 F for 30 min.  This can be done by putting to soil in black plastic bags and placing them in full sun.  Note that the more soil there is in the bag the longer it will take to get up to the right temperature.  

For more tips on reusing potting soil see:

Use it in the garden to lighten heavy soil.  Mixing old potting soil into heavy garden soil is a pretty effective means of adding long lasting organic matter to the soil.  I've done this and even after two seasons the soil is noticeably lighter and easier to work with.  The down side is that any viable seeds from your potted plants are now in your vegetable garden.  As a result I now have scarlet sage and torenia scattered through the vegetable garden.  Had I pasturized the soil this problem could have been avoided.

While my vegetables are planted in neat rows, volunteer seedlings are filling in all the gaps. 
This photo was taken in mid-July so the salvia has not yet reached full size - it gets 'worse.'

Throw it in the composter.  This should be a no brainer, but I had not considered it until I read about doing this recently.  Potting soil adds 'brown' material to the composter.  Since we use our composter mostly for kitchen waste (mostly 'green' or high nitrogen materials), it is in need of 'brown' or high carbon materials to balance it out.  After adding a load of old potting soil I noticed an almost immediate increase in composter temperature.  This practice also carries a risk of spreading seed from the potted plants, but if the compost gets up to temperature (120-140F) for several days most of those seeds will be killed (as will most plant pathogens).

Do you have any other tips for using old potting soil?  I would love to hear them.