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I have here tens of hectars red clover. What ever the weather or moisture of soil is, it gives nothing. Over 20 years ago I got sometimes a good late yield. At least clovers need 25C temp and moist soil to give nectar but even that does not suit to red clover.
I believe that red clover has been breeded to grow continuosly and it does not make nowadays nectar.
One example: there was 6 hectars blooming red clower in July. I saw only one bumble be in the fied.
Two weeks later, when all other flowers have bloomed away, there were 5 bumble bees per square meter. So 6 x 10 000 m2 x 5 bb/m2 = 300 000 bb on one field.
when red clover has been cut in the middle on summer and it blooms again 1 months later, it gives a good pollen to winter bee rearing here.
But normally, when red clover start to bloom, the farmer wraps the clower into white plastic balls to make forage.
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