This Year’s First Seed Harvest and Volunteers from Previous Years

Last week, we harvested our first Brassica rapa seed crops of the year. As we start this year’s harvest, I have also been watching some of the remnants of previous years’s seed crops.


The brassicas overwintered in a field tunnel and then flowered in April – a bit earlier than usual. I have been walking the brassica patch 2-3 times a week to make sure I notice when they set mature seed.

Walking across the field earlier this week, the yellow brownish plants (on the left and right of the picture) told me it was time time to harvest. The green plants (in the middle of the picture) are B. junceas, B. napuses and some garden cress that flowered later than the B. rapas.

Up close, I could see that the seedpods hadn’t matured and dried uniformily. This might be a consequence of the  mix of genetic material in this population (our winter brassicas have been quite crossed up as we strive for better cold tolerance), but I suspect some of the premature drying is due to structural damage from that heavy early May snowfall.

We cut the dried stalks, piled them in rubbermaids, and drove them to the barn.

We then laid the stalks on tarps in the barn with fans for air circulation. These plants will keep maturing for a couple more weeks before we thresh them.

I am not thrilled with how green some of the material is. We harvested because I could see seed starting to shatter on some branches, and this was the last sunny day in the forecast.


As we go about our normal farming duties, I always watch what’s happening elsewhere on the farm – evaluating crop maturity, considering soil dryness, trying to guess where that Kildeer nest is, or looking at weed pressure and what kind of weeds are in the garden – which in today’s post are volunteers from previous crops.

Some burgundy amaranth amidst a cover crop of oats and vetch. These are from seed that matured in our cut flower beds rather than in the seed garden. If I think about it later this week, and get around to crossing the farm to these beds, and we don’t mow the cover crop first; I’ll harvest some of these for mesclun salad mixes for market.

Strawberry spinach is taking over the oat cover crop in this corner of the seed garden. I am letting it mature in the undercanopy.

I didn’t harvest last year’s Strawberry Spinach seed crop in time, resulting in the current seed bank. This volunteer crop germinated in April and is almost mature – months earlier than my usual planting and harvest dates. For some reason, I thought this Chenopod was more of a heat lover and always waited to plant until the end of May. Seems I was wrong.

In the previous pictures, there are a lot of plants germinating from shattered seed.  In a cover crop, these can be managed by mowing before they set seed themselves. In a vegetable crop, that seed density would be a weedy problem. However …

This lone mustard in a block of onions is the only sign that I grew out spicy mustards, tatsoi, and dill, all for seed, in these same beds in 2006. I have found that the first year after a seed crop, the level of volunteers is significant, the second year is definitely noticeable, but after 3 years the level of most escaped seed from seed crops is minimal. Of course, this is in a context where we plan our cropping practices and ground management to flush out the soil seed bank.

Coming soon

This week is this blog’s half-year birthday. In my next post,  I will step back and look at what I’ve been writing for the last 6 months.

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