Eschalote Grise and Zebrune

[Jang]

I have grown Zebrune from seed this year and Eschalote Grise from sets. The contrast in size is remarkable. Zebrune has grown huge and is not dissimilar in appearance to a biennial onion variety like Tropea Lunga Rossa. Eschalote Grise multiplied vigorously (around 20 to each bulb) but each division was small, some very small.

As far as I can make out Zebrune seems to be universally grown from seed which is readily available . I assume that as it's described as a shallot it will divide if planted the next year .
And I wonder whether there's any way to encourage Eschalote Grise to produce fewer but larger divisions.

[Galina]

I did a mini trial with banana shallots but from a commercial packet. After some germination difficulties as they were obviously treated, I got some splitting, but not too many. A trial I did not continue. This is the old problem of knowing the difference between shallots and onions and whether or if banana shallots are in fact a third species.

Did you have any flowers on these Eschalote Grise? Growing from seed might give you the difference between small and slightly larger size. Bearing in mind that EG are supposed to be a separate species again, separate to other 'proper' shallots not of the banana shallot type, it is difficult to compare these.

[Jang]

I hadn’t taken in that Eschalote Grise is a separate species, Allium oschaninii. Interesting. No, there were no flowers; they were incredibly busy dividing.

I’ll hope to grow them again next year from my own sets and see if there’s any variation in the way they grow.

[jayb]

They look lovely

To my mind the commercially sourced banana 'shallots' grown from seed are not a dividing type or for that matter any of the seed sown shallots they offer. When planted the following year they will run to seed rather than soil divide.

[Jang]

Yes, I left one in by mistake last year. I think they did divide but also flowered, then collapsed before producing seed.

[triffid]

For growing larger Echalote Grise bulbs this may be helpful:

The size of bulbs harvested depends on the number of daughter bulbs formed per unit area, and this can be varied by two factors: the number of mother bulbs planted per unit area and/or their size. The growing points giving rise to daughter bulbs are already present in a mother bulb when it matures, and cannot be modified by storage conditions, planting date or
density. The number of daughter bulbs produced per mother bulb planted depends primarily on the weight of the mother bulb.

Hence, planting large mother bulbs at a high planting density results in a high density of daughter bulbs of small size, whereas planting small mother bulbs at low density results in a low density of daughter bulbs of large size. Table 6.1 shows the distribution of daughter bulbs that resulted from the extreme treatments in a French trial. The same size distribution of harvested bulbs can result from different combinations of mother bulb size and planting density, so long as they result in equal numbers of daughter bulbs. It can be seen from Table 6.1 that treatments gave a threefold difference in the number of daughter bulbs, but yield increased by a factor of only 1.3, so mean bulb size was much reduced from the heavier planting weight.

Brewster, J.L. Onions and Other Vegetable Alliums, 2nd Edition p.264

[Jang]

That’s absolutely fascinating and really useful.Thank you, Triffid. I had read Brewster’s book but the information registers far more when it becomes relevant to a need or wish. I will definitely experiment this next season.I have plenty of small bulbs to try low density planting with!

And yes, there’s a lot of waste with these. They have particularly hard skins. And I have so many very small bulbs that I’m pretty sure they won’t all get used.

I believe I planted 10 bulbs about 9” apart, and the bulbs were quite large as supplied. The spacing seemed adequate at the time, but I’ll go much wider, and with smaller bulbs, when I plant this autumn.

[triffid]

I've made the mistake of not reading the last sentence properly:
"Equations 6.4 and 6.5 were derived for spring-planted ‘Jersey demi-longue’shallots grown in western and central France and also apply to tropical shallots grown in the West Indies. Grey shallots (see Chapter 1) and autumn-planted shallots do not conform to these equations (Messiaen et al.,1993)."
They do not elaborate on what to expect from grey shallots and I can't access the study.

[Jang]

Thanks for your further elaboration. It seems to me still worth exploring the principle of more widely spaced planting.
On size of the mother shallot, perhaps the best idea is to try a range of sizes and see how they do.