#57 - Mar 2022 - Garden Stuff - © Sandy Lang - slang@xtra.co.nz
CLEVER SEEDSMarch/April: Early/mid-autumn. •Gardens need watering in autumn. Although rainfall and plant water use are about in balance, we still get dry periods and our sandy soils soon run out of water. •Now is transition time. Harvest and clear out summer crops and plant winter ones soon, while it’s still warm, so they get going before the cold.
Tiny sleepy plants: The new generation of plants is inside their seeds. After flowering, pollination and fertilisation, the embryo grows. But in the seed (now a tiny plant, already with root, shoot and leaf) it stops growing and dries out. Alive but dormant, it can sit there for a very long time - 32,000 years in a permafrost (campion) or 2,000 years in a dry desert (date). Most garden seeds will last several years if kept dry.
Experiment: To see one of these tiny dormant plants, soak a broad bean in water for 24 h to soften it. Peel off the leathery seed coat. Pull it apart. Inside you’ll see the tiny root, shoot and leaf (take a photo). Leave another bean in water for 4 or 5 days and you'll see the tiny plant has already woken up and started to grow.
Seed bank: To germinate, a seed needs just water and mild temperatures - bury a domesticated seed in moist soil, at room temperature, and it will germinate. But most wild seeds won’t. Domesticated seeds have been selected (by us) for quick germination. Wild seeds have been selected (by nature) to remain dormant for years. Why? So, they accumulate in the soil (a seed bank) with just a few germinating each year. Then, if this year’s lot of seedlings is wiped out by a pest, disease, drought, flood, fire or frost, next year’s lot will come up just as if nothing had happened. Makes sense. Plants are survivors…
Seed dormancy: Even when moisture, temperature and light are optimal, there are many ways seeds delay germination. (a) In some the seed coat is hard (stops the embryo expanding) or waterproof (stops it getting wet). (b) Some seeds have a chemical growth retardant. This is gradually broken down (slow chemistry) or leached out (repeated rainfall) – then the seed germinates. (c) Many seeds need a winter before germination. Stratification: You can simulate a winter by ‘stratifying’ wild seeds. Put them in a plastic bag, with a damp tissue, in the fridge, for 12 weeks. Then, back in the warm, they’ll germinate. Google seed dormancy wiki ___________________________________
CLEVER SEEDSMarch/April: Early/mid-autumn. •Gardens need watering in autumn. Although rainfall and plant water use are about in balance, we still get dry periods and our sandy soils soon run out of water. •Now is transition time. Harvest and clear out summer crops and plant winter ones soon, while it’s still warm, so they get going before the cold.
Tiny sleepy plants: The new generation of plants is inside their seeds. After flowering, pollination and fertilisation, the embryo grows. But in the seed (now a tiny plant, already with root, shoot and leaf) it stops growing and dries out. Alive but dormant, it can sit there for a very long time - 32,000 years in a permafrost (campion) or 2,000 years in a dry desert (date). Most garden seeds will last several years if kept dry.
Experiment: To see one of these tiny dormant plants, soak a broad bean in water for 24 h to soften it. Peel off the leathery seed coat. Pull it apart. Inside you’ll see the tiny root, shoot and leaf (take a photo). Leave another bean in water for 4 or 5 days and you'll see the tiny plant has already woken up and started to grow.
Seed bank: To germinate, a seed needs just water and mild temperatures - bury a domesticated seed in moist soil, at room temperature, and it will germinate. But most wild seeds won’t. Domesticated seeds have been selected (by us) for quick germination. Wild seeds have been selected (by nature) to remain dormant for years. Why? So, they accumulate in the soil (a seed bank) with just a few germinating each year. Then, if this year’s lot of seedlings is wiped out by a pest, disease, drought, flood, fire or frost, next year’s lot will come up just as if nothing had happened. Makes sense. Plants are survivors…
Seed dormancy: Even when moisture, temperature and light are optimal, there are many ways seeds delay germination. (a) In some the seed coat is hard (stops the embryo expanding) or waterproof (stops it getting wet). (b) Some seeds have a chemical growth retardant. This is gradually broken down (slow chemistry) or leached out (repeated rainfall) – then the seed germinates. (c) Many seeds need a winter before germination. Stratification: You can simulate a winter by ‘stratifying’ wild seeds. Put them in a plastic bag, with a damp tissue, in the fridge, for 12 weeks. Then, back in the warm, they’ll germinate. Google seed dormancy wiki ___________________________________