Potting mix considerations

I have been doing a lot of thinking and reading about potting mix recently. For one thing, it is only four months till we start seedlings for 2016! (And only a month or so before we winter plant seed for perennials.) For another thing, I am thinking about using lots of wicking planters for greens in the upcoming year to improve their survival in our dry climate. Finally, a movable greenhouse has many benefits. I have been considering making our hoop house on the Littleton farm moveable. That way, we could start hardy spring greens, and then, once they were going and the weather was a bit more moderate, I could slide it away and start summer seedlings on the new site. Right now, spring plants languish in the increasing heat in the house, while delaying the summer tomatoes and peppers, and the tomatoes keep out the Fall kale and lettuce. However, a movable greenhouse is a big investment, and it might be better to just plant everything in containers, and then move and swap those. An unproven idea that we might try.

Anyway, there are lots of reasons for me to be considering potting mix strategies right now. For the past ten years or so, I have been using compost/ peat/ perlite type potting mixes. They are a logical extension to my organic gardening philosophy of feeding the soil, not the plant. However, I just now did some research and found a forum thread where a member was advocating a bark/ peat/ perlite mix, with the ratios being 5 1 1, very light and airy. They then add some commercial slow release inorganic fertilizer. The reasoning behind this is that a pot of fine grained potting mix contains a perched water table, where the natural attraction of the water to the soil particles is greater then gravitational pull. This zone becomes airless and is off limits to roots. So, some advocate separating the two functions of potting mix; structural support, and the provisions of nutrients.  Of course, this is just what conventional farmers do; they view the soil as an inert medium for holding plant roots, and then douse the soil with chemical fertilizer. However, since the pot is already an artificial growing area with different conditions then the soil, it makes sense that a different approach might be warranted. As an organic gardener, I would use organic slow release fertilizer, or a liquid fish/ kelp product if I switch over to a coarse grained medium.

I may do some experiments to compare the two approaches.

I also may include a small pot or bag of worm castings in larger, long term pots, which would provide fertilization without gumming up the whole pot.

Here is a link to the forum thread that got me interested in this: http://forums2.gardenweb.com/discussions/2842847/container-soils-water-movement-and-retention-xxii?n=329


The third week of March

In Littleton this week we rented a trencher and installed a water line and frost proof hydrant. We were donated a bunch of plastic storage units for our tools and supplies. Somebody also donated a picnic table and benches.

We planted flats of Sugar Daddy snap peas, Purple top white globe turnip, Yellow Granex onion, and radishes in the Littleton greenhouse under row cover, using our standard potting mix. We planted some small news paper pots of Sugar snap peas. (The greenhouse is unheated: however, at this time of year the double coverage should keep things from freezing.) We planted about 250 sweet peppers (Marconi Red, Jimmy Nardello, Ampuis, California wonder red, California wonder orange, and a few others) and 100 eggplant (Early black and Black Beauty) in plastic six pack with our standard mix. The peppers and eggplant are now in a heated frame at my house.

We started to pin down landscape fabric in our work area, which will eventually be covered by mulch or gravel.

In Lakewood, we decided that the old compost/ mulch area was unsightly and not very functional. We started the process of tearing down the old bins and forking out the compost materials. (Things did not decompose very well; they seem to have dried out.) We will be building new bins in the shade of the greenhouse, screened from view by a grape and kiwi arbor. We forked over 300 square feet of the beds that we rototilled last year to remove the grass, and re-mulched the paths. We also started gathering and piling all the rocks and concrete chunks on site to build a raised rock flower bed.

Notes from the work day April 2nd

At this work day, we got a new compost pile started, and cleared an area to start building permanent compost bins out of the wire we have salvaged from the fence. We began lining our keyhole beds with stones to define them, and building mini terraces across the slope with the larger rocks and concrete chunks we have dug up. These will stop the sheet mulch beds from gradually migrating downhill. We discussed renting a pole chain saw and large chipper to turn unwanted tree limbs into mulch.

Notes from the Work Day, March 29th

At this meeting we started rebuilding our compost pile for the spring. We got more logs and branches out of the ditch, and more tree trimming done. Half the fence along the North side of the property is now clear of the old wire and debris, and the posts have been dug out and straightened, ready for the new wire. Our logo has been painted on our new sign, so now we just have to set a post and get a hanger for it. We set dates for upcoming projects, and discussed tree planting, fence repairs, bed edging, compost bins, and other topics. A load of deciduous tree mulch was delivered, and another of evergreen mulch. We will be using the evergreen mulch immediately for paths, and mixing the deciduous tree mulch together with manure to create a hot compost pile, since this will kill any borers present in the chips (if any.)

Greenhouse construction, Phase one/ Notes from the meeting of December 3rd

At this meeting we got the frame of our Greenhouse put up. We bent inserted lengths of rebar into PVC pipe, and bent the rods into hoops, inserted about a foot into the ground. We then joined them at the top with another length of PVC/ rebar. The rebar provides the strength, and the PVC keeps the rebar from abrading the plastic cover. S30A0132

Due to the wind, which picked up towards the end of our meeting, we were unable to get the plastic cover attached. It would have been buried along the sides of the greenhouse. We also need to build a wooden frame at one end to contain a door and vent. Once we get this done, we will install an inner hot bed for starting seedlings, low tech insulation on the north side, mass to collect solar heat and even out temperature swings, and possibly a compost heating system. These systems will be backed up by an electric heater.

Notes from the meeting of November the 14th/ Greenhouse Design

The weather is still fairly pleasant, so we have continued working on our Lakewood Farm. At this meeting we continued turning our abundant supply of leaves into compost piles.

We also discussed plans for our greenhouse. It will be a simple hoop house, which has the advantages of low cost and ease of construction/removal. However, it will be less sturdy and harder to heat.

We will thread twenty foot lengths of rebar into pvc pipes, and bend the composite rods into hoops. These will be buried in the ground, and connected along the top by another rod. Then greenhouse film will be draped over the structure, and buried along the edges. Rope will be used to tie down the plastic and keep it from flapping in the wind.

Hopefully, we will be able to construct the greenhouse at the meeting after next. I will post pictures of the construction, and then record its performance. This is an Eliot Coleman style greenhouse, and part of it will be used for early plantings of cool weather crops. It will also house a hot bed for starting seedlings in the spring.  These will be for sale, for member’s gardens, and for our farm site.

Notes from the meeting of November 7th

At this meeting, we got a hot compost pile started. We are layering leaves, manure, and coffee grounds in an eight by eight foot wire mesh bin. We also added a little blood meal. Sufficient nitrogen causes a compost pile to heat up. However, the manure we are using may not have enough nitrogen in it; the manure pile had not heated up. And we did not have enough blood meal and coffee grounds to heat up the pile by themselves.  If, by next week, the pile shows no signs of heating, we will add some more nitrogen.

We had some lawn care companies dump leaves. In fact, we got too many leaves (if that can be possible.) And the truck drivers dumped leaves right on top of our sheet mulch garden beds, where it may prove difficult to rake them up without raking up the sheet mulch. These leaves will be hot composted, since we do not know where they came from or what they might contain. We have already picked out some trash. A hot compost pile will break down almost all chemicals, and kill pathogens. The only common contaminants which a hot compost pile can’t get rid of are heavy metals and certain extremely long lasting herbicides. Heavy metals should not be a problem in leaves. People don’t spray herbicides on their trees. By the time the leaves land on the lawn, there should be very little herbicide present on the surface, and even less would end up in raked leaves. To insure that this reasoning is correct, we will be testing all finished compost before adding it to the garden beds. Compost can be tested simply for quality by planting a few radishes or other inexpensive seeds in it.
We got our first set of professional soil tests back. The cheap home soil test had rather inaccurate results. We will not need to add any nutrients to the soil except nitrogen, since we actually have overabundant levels of many nutrients. The pH is 7.8, which has an advantage. It will bind with any heavy metals which might be present, keeping them from being taken up by plants. The only common heavy metal for which this will not work is arsenic. In a few weeks we should have our heavy metal soil test results back. The high nutrient levels may have been caused by a chemical fertilizer overdose by the previous owner.

Notes from the meeting of August 22nd

This meeting was held on our farm site in Lakewood. Due to a number of factors, we were unable to get any sheet mulching done. However, were were able to talk over a lot of things, and we will hopefully get the sheet mulching done next time. (This time the truck which was supposed to be delivering wood chips broke down, and we got a call to that effect about fifteen minutes before the meeting was due to start. But they think they can get it to us by next week. )

A schematic plan for the land was drawn up and debated. I will be posting this, but I have decided to refine it a little first.  Its main feature was the arrangement of the orchard so as to leave sufficient solar access for a self-heating greenhouse.

For those who might not know, sheet mulching means laying down a layer of overlapping cardboard, which smothers weeds, and then piling on about a foot of mulch. A blend of high nitrogen and high carbon materials are used, so it is rather like composting in place. It eliminates all digging, and a lot of weeding, watering, and fertilizing. However, even though we are using this method for our first garden on this site, we will have a few other types for comparison. This especially since some members at previous meetings have expressed an interest in other styles, among them waffle gardens and Biointensive/ French intensive.

Among the points discussed were the following:

It is very important to use crop rotation. To do this, we will have to section off various types of crops, though we can still use companion planting, as suggested at a previous meeting.

We can take advantage of the land slope to grow both water loving and dry tolerant crops. Among other things, corn was suggested for the higher land.

We will use Open Pollinated (OP) crops only for community plantings, but hybrids can be used on member’s individual plots. All Heirlooms are OPs, but not all OPs are heirlooms. New OPs are being breed all the time, by small companies and individual plant breeders; they will be the heirlooms of tomorrow. OP means that a strain is not hybridized or GMO, and will come true from seed.

The fence is in worse shape than we thought, and will require large amounts of work, and potentially quite a bit of money, to get it back into shape. However, the funds might be able to be generated by building and selling beehives. We will see.

A member suggested putting composting worms in any compost piles. I think this is a good idea.

Among the crops suggested, besides all the standard vegetables, were corn, potatoes, strawberries, melons, and grapes.

We could grow rare heirloom corns, thus saving valuable genetics from extinction.

We will use key-hole beds. These are rather hard to visualize or describe; you can find images online. They save on path space, look interesting, and can function as sun traps . .  or the reverse.

We will put in some sitting areas out in the field.

Here is a link to my earlier post on Permaculture, which influences the emerging layout of the land.