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.

Skirting

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.

Hoophouse

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.

Successes

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.

Problems

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.

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.

Qty	Latin name	Common name
1	Agastache foeniculum	Anise hyssop
1	Brassica oleracea acephala	Tree collards
3	Brassica oleracea acephala	'Western Front' perennial kale
1	Crambe cordifolia	Giant sea kale
2	Crambe maritima	Sea kale
1	Foeniculum vulgare	Fennel
2	Malva sylvestris mauritiana	Zebra mallow
1	Malva moschata	Musk mallow
2	Melissa officinalis	Lemon balm
1	Myrrhis odorata	Sweet cicely
2	Rumex scutatus or R. acetosa	French Sorrel
6 sf	Scorzonera hispanica	Scorzonera

Groundcovers

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

Latin name	Common name
Barbarea verna	Wintercress
Campanula portenschlagiana	Bellflower
Campanula poscharskyana	Trailing bellflower
Claytonia montia	Miner's lettuce
Claytonia siberica	Siberian miner's lettuce
Diplotaxis tenuifolia	Sylvetta arugala
Origanum spp	Oregano species
Oxalis oregona	Redwood sorrel
Rumex acetosella	Sheeps sorrel
Sanguisorba minor	Salad burnet
Stellaria media	Chickweed
Taraxacum officianale	Dandelion
Thymus spp	Thyme species
Viola spp	Violets

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 name	Common name
Allium ampeloprasum	Elephant garlic / Leek
A. cepa 'proliferum'	Egyptian walking onion
Allium cernuum	Nodding onion
Allium fistulosum	Bunching onion
Allium sativum	Garlic
Allium schoenoprasum	Chives
Allium tuberosum	Garlic 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.

Qty	Latin name	Common name
1	Agastache foeniculum	Anise hyssop
5	Anthriscus sylvestris	Woodland chervile
2	Aquilegia vulgaris	Columbine
4	Asphodeline lutea	Yellow asphodel
2-3	Bunias orientalis	Turkish rocket
4	Campanula rapunculoides, C. persicifolia, and other tall species	Bellflowers
10	Chenopodium bonus-henricus	Good King Henry
2	Crambe maritima	Sea kale
1-2	Foeniculum vulgare	Fennel
1	Levisticum officinale	Lovage
1	Lycium barbarum	Wolfberry
6sf	Mentha spicata	Spearmint
1-2	Myrrhis odorata	Sweet cicely
3-4	Oenothera biennis	Evening primrose
3	Rumex scutatus or R. acetosia	French sorrel
2	Smyrnium olusatrum	Alexanders
1	Symphytum officinalis	Comfrey
10sf	Urtica dioica	Stinging nettles

Zone 2 Stems & Shoots

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

Latin name	Common name
Arctium lappa or A. minor	Burdock
Asparagus officinalis	Asparagus
Maianthemum racemosum	False solomon's seal
Petasites frigidus	Sweet Coltsfoot
Petasites japonicus	Fuki
Polygonatum biflorum and P. commutatum	Solomon's seal
Rheum x cultorum	Rhubarb

Zone 2 Weeds

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

Latin name	Common name
Borago officinalis	Borage
Calendula officinalis	Calendula
Cardamine unknown	Popweed
Geum urbanum	Clove root
Lamium purpuruem	Purple dead nettle
Lapsana communis	Nipplewort
Phytolacca americana	Pokeweed
Solanum nigrum	Black nightshade
Taraxacum officinale	Dandelion