Amanda Bramble of Ampersand Sustainable Learning Talks about Greenhouse Farming @ Arcosanti


Amanda Bramble is the founder of Ampersand Sustainable Learning a center in New Mexico that promotes sustainable development and approach tech through workshops offered there. She spent time at Arcosanti in the late 90s as the Garden Manager.

We compiled some questions for her and others experiences in the Arcosanti Camp Greenhouse management over the years at Arcosanti. I presented the questions to her in a phone conversation in relation to our request for more information for data about the Greenhouse. The context of this discussion was in relation to our plan to develop a prototype greenhouse to grow food at Arcosanti.

Arcosanti Camp Greenhouse

Below are my notes (and Amanda’s added inputs and comments) from a conversation we had a few weeks ago.

What is the performance in the summer?

The camp greenhouse tomato plants grow well if shading and misting is good. Ventilation is important. The low vents on the south side and high on the North side worked well. Designing vents oriented towards prevailing winds is a good idea. Also she suggested that we put cloth wicking up water or some similar evaporative cooling system to reduce the GH temps. Or misters from above on a timer.

I grew lettuce, herbs like borage and calendula and nasturtium (edible flowers) and parsley in the summer. Actually all of these as well as cukes and bell peppers and winter squash (with vertical climbing areas) can be started at the end of winter, around february. The tomatoes can be grown as perennials for several years, but fruit production does decline after a couple years. Expect there to be a rest period in the heat of the summer- it may be too hot for pollination and in the winter when there is not enough light to encourage fruiting. Train and prune tomatoes and other climbing plants to be manageable for harvest. They can easily get out of control and create dense areas that promote bug problems.

What shade is best?

Shading is important and less light is an advantage because you reduce the temps. With lettuces, kale and chard and other greens, the leaves actually get bigger to absorb the reduced sunlight coming into the greenhouse. Lettuce can be grown all summer under shade. Start new plants every two weeks or so. The plants will go to seed and get bitter sooner in the summer heat. Try heat resistant varieties. Convection (Wind) coupled with moisture is how you can cool the greenhouse other than shading.

Amanda says she shaded under the plastic. However, stretching the shade cloth on top of the plastic may be more effective and extend the life of the plastic.

What Plants that do well in the GH overall?

  1. Tomatoes
  2. Greens
  3. Peas
  4. Peppers- serrano pepper bush did well
  5. Parsley
  6. Lemon Verbena

What grows well in Winter?

  1. Non fruiting plants
  2. Greens

Note: She says “It is important to plant successively and take advantage of growing in early spring before it gets hot but when it’s still too cold to grow outside.”

How does Camp GH ventilate?

The typical problem was too much heat. To solve this they tried shading and misting. Shading on outside is better than on inside, because the heat from the shading system is not building up on the inside of the GH. A low vent/high vent system works well for keeping greenhouse cooler. She says it’s “also helpful to make sure that the vents are screened at least on the bottom from rodents, but not from insects. 1/2″ mesh is good.”

What would you change?

She recalls that there were some issues with the Dehydrator and said it was hard to dry during monsoon when the humidity was high. The solar dehydrator is a great thing and good thought was put into the way this one was designed into the greenhouse. But there should be a wall and an easy door to separate greenhouse moisture from the dehydrator area.

Too much concrete was used in the construction process of Camp Greenhouse. She feels the use of more earthen material would have been better. It seemed to keep the greenhouse hotter than it needed to be – all the thermal mass exposed to the sun during the summer. During the winter that would be good. She says that she “now prefers greenhouses that have vertical walls that emit light all the way into the space during the winter to heat the thermal mass. During the summer the sun is more over head and the thermal mass can be not in the path of the sun. The ceiling of the greenhouse has some insulation and removable shading for summer.”

Beds connected to the earth would have been best.

We also talked about a thermal water storage system as a way to store heat for keeping the greenhouses warm in the evening. She said about 5 gal/sq ft is a good general number.

The fan into the rock storage didn’t work: “I tried to make this work but it didn’t seem to make a difference.”

Other comments:

During her time running the Camp Greenhouse she placed the starts in the pathway to better use space in the greenhouse. Although this reduced the space, she said she could work around it – start seeds at base of pathway of next bed.

Successive planting every two weeks is good to start a flat so that the harvest are staggered.

Using Greywater in Camp GH is one thing that Amanda considered. She uses pumice in her system as a wicking system. Plants pull up the water from the pumice wick.

Please check out the book The Solar Greenhouse written by Bill Yanda and Rick Fisher. She says there are all kinds of calculations useful to our project there.

Perennial food plants could include tropical fruits- these will probably do better with unlined, open beds.

Amanda notes the importance of value added production:

One crucial aspect to any sustainable food system is food processing and storage. True sustainability would not involve fossil fuel based refrigeration. Moving in that direction would mean designated space and planned interconnection with food processing areas which would heavily rely on dehydration (sun dried tomatoes, fruit leathers, so much more). Cooking and canning would ideally be based on passive solar ovens and cookers. This would be a great business opportinity as well, making value added products that can be sold year round. Fermentation is another great sustainable food preservation technique. Maybe you could grow ginger in the greenhouse and make kimchi!

As far rain collection her opinion is that it should be design in tandem with the rest of the structure. Rain collection should be done as an afterthought which really limits its effectiveness. Amanda’s experiences and research tells her that it “should be designed so that the storage is big enough and that the greenhouse is set up to use this as a primary water system.” The rain collection tank can be partially filled with well water when needed, using the same plumbing for irrigation.

She mentions Edible Schoolyard noting that they do a good job with integrating the garden and kitchen.

She says in earlier email that “a funded greenhouse manager is important- but also getting dedicated food processing support is crucial to make the greenhouse manager worth being funded. Especially being so far from an outside market. Being prepared to process the food on site when the food needs it will really reduce waste and increase sustainability. This could be integrated into the workshops, of course.”

More about Ampersand Sustainable Learning

Ampersand Sustainable Learning Center in Cerrillos, New Mexico, is a place to explore sustainable living.   Our off-grid site demonstrates sustainable systems including permaculture, land restoration, organic gardening, passive solar design, and wise water techniques. We build with natural and salvaged materials, cook with solar ovens, and rely on rain catchment.

Arco Alums Dr Sparks (Michael Bittman) and Patrick Doyle help with construction of straw bale building at Ampersand.

Please see their website for more info: www.ampersandproject.org

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