Thursday, July 17, 2014

Hoophouse on the Slug Moat

In fall of 2011 I built our slug moat to protect nursery pots from slugs while providing rainwater catchment and other typical aquatic benefits. A few months later, to prepare for spring and make the most of the contraption, I added a hoophouse over the nursery table to provide a warmer, protected microclimate for the plants, without interfering with the use of the pond as an irrigation source.

Duck Integration

I wanted ducks to use the pond, but knew that with unrestricted access they would trash such a tiny area, destroying all plants and fish and filling the pond with poop and stirred up muck. To exclude ducks from enough of the pond to allow sheltering of fish and growth of poop-filtering cattails, I put a fence across the middle of the pond and around the excluded perimeter. Ducks could still be allowed into the protected area periodically, under close supervision.

I constructed a little ramp to make it easier for the ducks to get in and of the water.


Using thin plastic which had wrapped our lumber deliveries, I constructed a skirting sandwiched onto the table sides and posts with lathe and hanging to the water below. I hoped this would create a lower seal preventing air from coming up into the nursery table.


Next, I built a ventable upper enclosure for the plants from clear vapor barrier plastic left over from the house project. I created the end "wall" closest to the house by rolling a piece of lathe into a short piece of plastic, clamping it closed with three strong binder clips. I secured the lower half of this plastic to the vertical posts with more lathe, and tacked a couple of nails into the posts to allow the wall to be "hung" up for closure, or unhooked from the nails to half-open that end of the hoop house.

Since I didn't have posts to work with at the far end of the table, I used a single large piece of plastic for the rest of the hoop house, supported by plastic hoops screwed to the sides of the table, and draping down as the far wall. I used more binder clips to seal the junction between the large piece of plastic and the end wall, unclipping as necessary to move the sheets for ventilation.

I secured the sides by creating a small gap between the existing pallets on top and new wood I attached to the table sides just below. Tucking the plastic into the gap and wedging in some lathe created a strong seal, while allowing easy access or ventilation of the sides by pulling out the lathe.


On the whole, it worked. It definitely created a warmer microclimate and allowed faster early spring growth of the plants. Using all scrap materials, it had a distinctly amateur look to it, but was fairly easy to use for ventilating and accessing plants. I'm especially pleased with the side attachments of wedged lathe, which worked surprisingly well.


Despite lathe sandwiching it to the posts as low as possible, the lowest part of the skirting, pushed outwards by the concrete pier blocks, tended to blow around, failing to make a reliable seal. Often the skirting got stuck on the perimeter fence, potentially negating the slug-proofing function of the slug moat. The plastic scrap I used was just barely long enough to reach the water surface; with more material to work with I could have wrapped the bottom with some weights to ensure a straight drop to the pond.

The cross fence within the pond was of very flimsy construction and even flimsier attachment. A fence could have been secured to two of the table legs and anchored against their concrete piers stacked in the water below, but the placement of the table within the pond didn't make sense for that. It would have created either too tiny a pond for the ducks to use, or too small an area for plants to grow without duck disturbance.

The perimeter fencing, secured very loosely with metal stakes salvaged from political yard signs, also failed to inspire confidence. Neither the perimeter nor the internal fence were tested long-term against inquisitive ducks, and I suspect both would have required some adjustment and fiddling.

The binder clips came loose easily from slippery plastic, both where I wrapped lathe into the plastic to create the end wall and especially where I tried to clip the two upper sheets together. Again, I was using pieces just barely long enough to meet, so any significant wind put a lot of force on the joints. Slightly longer pieces with more overlap and slack would have helped. Ultimately the system needed a better connector - perhaps snap-on grommets.

Saturday, July 12, 2014

Perennial Greens Planting Plan

Zone 1, extending into zone 2. From bottom center, working counter-clockwise:
Giant sea kale, sweet cicely in seed, turkish rocket, zebra mallow in flower, perennial kale in seed, lemon balm, french sorrel in seed, borage in flower, elephant garlic in flower, sylvetta arugula in flower, and nipplewort.
Also skirret & chinese dogwood in background, with crocosmia in foreground.

Two mistakes I made in my perennial vegetable experimentations in Portland:

  1. I overplanted perennial greens, more than we could possibly eat.
  2. I planted the greens over a large area, forcing more traversal of the yard than necessary. Though walking the yard to pick greens helps keep an eye on everything, it's inefficient to go further than necessary on a nearly daily basis.

Before we sold the house, I was consolidating a core set of perennial greens into approximately 100 square feet of beds closest to the house. This brought the front yard garden into better alignment with design by zones, with a tight zone 1 producing the majority of the daily pickings for two adults (leaves & flowers, salads & cooked), and freeing up zone 2 for root crops and less frequently harvested vegetables. I still envisioned picking from zone 2, from deliberate plantings and from edible weeds, a few times a week for variety and to augment zone 1 production.

This design took advantage of the fact that, for much of the year, the house shades most of the front yard area closest to it (especially after we raised the house 3'.) Most of the perennial greens should do well in partial to full shade, whereas the root crops and annuals generally need more sun. Most herbs also want full sun, and we found we didn't need to pick them with each batch of greens, so the larger ones made more sense for us in zone 2.

Writing this up two years later, I don't remember the exact number of which plants I moved into zone 1, but I believe I've come close below. It's a good starting point; you'll need to experiment anyway with what works well in your site and what you like to eat. Regardless of the exact species composition, the end result of densely planted perennials should be a yield of greens requiring little to no work besides harvest - more or less no need to dig soil, replant, or weed. (And year-round, at least in Portland and similarly mild winter climates.)

Large Plants

Usually planted 2-3' apart. You can perhaps get away with closer spacing in a heavily harvested zone 1, but I'd be inclined to still give them full spacing.

QtyLatin nameCommon name
1Agastache foeniculumAnise hyssop
1Brassica oleracea acephalaTree collards
3Brassica oleracea acephala'Western Front' perennial kale
1Crambe cordifoliaGiant sea kale
2Crambe maritimaSea kale
1Foeniculum vulgareFennel
2Malva sylvestris mauritianaZebra mallow
1Malva moschataMusk mallow
2Melissa officinalisLemon balm
1Myrrhis odorataSweet cicely
2Rumex scutatus or R. acetosaFrench Sorrel
6 sfScorzonera hispanicaScorzonera


These can be planted under and around the large plants, to exclude weeds and provide bonus greens & flowers.

Latin nameCommon name
Barbarea vernaWintercress
Campanula portenschlagianaBellflower
Campanula poscharskyanaTrailing bellflower
Claytonia montiaMiner's lettuce
Claytonia sibericaSiberian miner's lettuce
Diplotaxis tenuifoliaSylvetta arugala
Origanum sppOregano species
Oxalis oregonaRedwood sorrel
Rumex acetosellaSheeps sorrel
Sanguisorba minorSalad burnet
Stellaria mediaChickweed
Taraxacum officianaleDandelion
Thymus sppThyme species
Viola sppViolets

Bed Edges

We used a lot of Allium greens, finding them much easier to grow than bulbing onions. These work well along the edges of beds, helping delineate the pathways.

Latin nameCommon name
Allium ampeloprasumElephant garlic / Leek
A. cepa 'proliferum'Egyptian walking onion
Allium cernuumNodding onion
Allium fistulosumBunching onion
Allium sativumGarlic
Allium schoenoprasumChives
Allium tuberosumGarlic chives

Zone 2 Greens

If you have more room available, I would experiment with these. For species already listed above, numbers given are in addition to the quantity in zone 1. These are just for greens and flowers; not considering root and seed harvests of things like yellow asphodel and good king henry.

QtyLatin nameCommon name
1Agastache foeniculumAnise hyssop
5Anthriscus sylvestrisWoodland chervile
2Aquilegia vulgarisColumbine
4Asphodeline luteaYellow asphodel
2-3Bunias orientalisTurkish rocket
4Campanula rapunculoides, C. persicifolia, and other tall speciesBellflowers
10Chenopodium bonus-henricusGood King Henry
2Crambe maritimaSea kale
1-2Foeniculum vulgareFennel
1Levisticum officinaleLovage
1Lycium barbarumWolfberry
6sfMentha spicataSpearmint
1-2Myrrhis odorataSweet cicely
3-4Oenothera biennisEvening primrose
3Rumex scutatus or R. acetosiaFrench sorrel
2Smyrnium olusatrumAlexanders
1Symphytum officinalisComfrey
10sfUrtica dioicaStinging nettles

Zone 2 Stems & Shoots

Other vegetables nice to grow for something other than greens and flowers.

Latin nameCommon name
Arctium lappa or A. minorBurdock
Asparagus officinalisAsparagus
Maianthemum racemosumFalse solomon's seal
Petasites frigidusSweet Coltsfoot
Petasites japonicusFuki
Polygonatum biflorum and P. commutatumSolomon's seal
Rheum x cultorumRhubarb

Zone 2 Weeds

Volunteers that often need to be kept in check. We generally ate these rather than weeding per se.

Latin nameCommon name
Borago officinalisBorage
Calendula officinalisCalendula
Cardamine unknownPopweed
Geum urbanumClove root
Lamium purpuruemPurple dead nettle
Lapsana communisNipplewort
Phytolacca americanaPokeweed
Solanum nigrumBlack nightshade
Taraxacum officinaleDandelion