Here’s my new Season Extension slideshow that I presented recently for the Allegheny Mountain Institute Farm at Augusta Health and the Center for Rural Culture in Goochland. Click the diagonal arrow icon to see it full screen.
https://www.slideshare.net/SustainableMarketFarming/season-extension-pam-dawling
Photo Bridget Aleshire
Since Hurricane Michael passed by, temperatures have plummeted. I dusted off our Frost Alert List. First is the “Grab and Run” list of what to do. Then follows a list of factors to consider to help you forecast whether or not you are likely to get a frost. We take the night-time low temperature for our nearest town (7 miles away) and subtract 5F to predict what temperature we’ll get.
| Frost Alert List | |||
| Task | Crop | Notes | |
| Harvest all edible | Asparagus beans | ||
| Harvest all edible | Eggplant | ||
| Harvest all edible | Okra | ||
| Harvest all edible | Tomatoes | Incl green | |
| Harvest all edible | Peppers exposed to the sky | ||
| Harvest all edible | West Indian gherkins | ||
| Harvest all edible | Pickling cucumbers | ||
| Harvest all edible | Corn | ||
| Harvest all edible | Green bean plantings past their prime | ||
| Thick row cover | Late Beans #5,6 | Uncover once mild again | |
| Thick row cover | Summer squash and zucchini | Spring hoops or none. Ditto | |
| Thick row cover | Slicing cucumbers | Spring hoops or none. Ditto | |
| Thick row cover | Celery | Double hoops -leave covered | |
| Thick row cover | Last lettuce bed | Double hoops – leave covered | |
| Set sprinklers | Slicer tomatoes | Overnight from before 32F till after sun shines on plants | |
| Set sprinklers | Roma paste tomatoes and peppers | Ditto | |
| Set sprinklers | Other vulnerable crops | Ditto | |
| Frost is more likely on our farm if. . . | |||
| Date is after 10/14 | |||
| Daytime high temperature is less than 70F (21C) | |||
| Sky is clear | |||
| Sunset temperature is less than 50F (10C) | |||
| Dewpoint forecast (Louisa minus 5) is less than 43F (6C). | |||
| Wunderground 3.30pm forecast for Louisa low temp is less than 38F (3.5C) | |||
| Little or no breeze (But see last point in list) | |||
| Soil is cool and dry | |||
| If temps are falling fast, the sky is clear, and it’s windy (esp from NW), it may be polar air moving in and we could get a hard freeze. | |||
Photo Lori Katz
Photo FAO
If you want to understand frost much more than you do, see
Frost Protection: Fundamentals, Practice and Economics FAO.pdf
126 page resource on methods of frost protection, frost damage physiology, frost forecasting, passive and active protection methods, appropriate technologies, and reference material.
If you are pondering hoop systems for rowcover, here are our winter double hoops. The inner hoop is from 9 or 10 gauge wire, bent round a jig to make eyes. The outer hoop is 22 gauge wire and has the ends bent into hooks. We set the inner hoops every 6′ (2 m) along the bed, fit the rowcover, and roll its edges around wood stakes. then we add the outer hoops, hooking them into the ground-level eyes of the inner hoops. Lastly we tension the rowcover lengthwise. The outer hoops stop the rowcover from blowing away, and hole it in place when we push the edges up to harvest.
Pam Dawling
Photo Bridget Aleahire