An Inquiry into the Viability of Out-of-Date Seeds

Marica Bernstein, Department of Redundancy Department, Farther Along Farm University

Abstract

We planted some old seeds and will see what happens.

Introduction

Commercial seed packets for home gardens are labeled with sell-by or plant-by dates which refer to the year in which the seed crop was harvested; seeds sold for planting in the current year were harvested the prior year. These dates fail to take into account that nearly are seeds are viable, i.e., will germinate, for several years after harvest, especially if they have been stored under optimal conditions of temperature and humidity.

Being in possession of hundreds of seed packets packed for years earlier than 2020, and wanting to maximize the harvest of the current growing season, we sowed seeds in several mediums under various conditions correlated to the age of the seed. Given the non-optimal conditions under which these seeds had been stored, [fn1] we hypothesize that seeds older than five years, ‘Old Seed’ (OS), will fail spectacularly and the time and little effort we put into planting them will have been wasted. We further hypothesize, however, that seeds five years old or less, ‘New Seed’ (NS), will produce viable seedlings available for transplant into our summer garden. Success will vary according to species. [fn2]

Methods

Selection: Seeds were first sorted as to seasonality. Cool season species were not included. Seeds were then sorted as to OS or NS. Seeds older than 2010 were rejected out of hand, as were seeds needing scarification. [fn3]

OS Set Up: Containers of various shapes and sizes were collected from among the dozens sitting in the make-shift potting shed on the lower portion of the patio. These had previously been planted with an assortment of annuals and container vegetables. Planting medium ranged from commercial potting soil to common dirt or a combination. No effort was taken to amend the medium, although fertilizer pellets were visible in some. Seeds were planted or over-planted at approximately the recommended depth and watered in. Containers were labeled using plastic knives. See Figure 1 (background).

NS Set Up Materials and Apparatus: Two seed pack trays, two tray covers, 27 three-inch square plastic pots, and six 4-packs were obtained from the remarkably well-organized shelves in Tiger’s Workshop. These were rinsed, washed, treated with a dilute bleach solution, and left to dry in the sun. A three-quarter full bag of legitimate potting soil was removed from a plastic tub, also in the Workshop. A seed starting warming mat was eventually re-discovered on a box of books in the defunct Pool House. It was washed, treated with bleach, and tested. To monitor potting soil surface temperature, an infrared thermometer was gotten from the kitchen counter. To monitor soil depth temperature, an instant oven thermometer (previously designated for this purpose) was gotten from the Bunkhouse. As with OS pots, plastic knives were used as labels, though these had been rinsed in bleach water.

NS Procedure: Pots and 4-packs were filled with potting soil and seeds were planted or over-planted, and watered in. Pots and packs were labeled, placed in trays, and covered. Covered trays were placed on heat mat in a Gorilla Cart which receives full sun until mid-afternoon. Soil and surface temperature are monitored periodically, and covers placed, or removed, accordingly to maintain a near constant optimal temperature of 85°F.

NS Set Up Adjustments to Materials and Apparatus. The temperature reading taken at approximately 7:30pm suggested that additional measures were necessary to maintain a constant optimal temperature over night. Two cloches (Workshop) and two shop lights fitted with 100W bulbs (Bunkhouse storeroom) [fn4] were thus incorporated into the set up. See Figure 2.

Results

So far so good.

Footnotes

1 Sitting in a little cabinet in front of a window in the Bunkhouse and thus subjected to wild variation in temp & humidity.

2 I had forgotten how awful writing like this is. And it didn’t used to be that way. Science writing used to be way more entertaining and interesting. 

3 B/c I do actually have a life. 

4 I still have a stockpile of 100W incandescent bulbs. They come in handy!