I'm a big fan of brassicas. Especially the Japanese and Chinese types. Most all common economically significant (meaning grown as food crops) brassicas are pretty much known for being pretty reliable cool weather crops. Many of them (like a host of leafy...non fruit bearing cultivars) don't do so well in the heat. Some varieties of things do better than others even within the same 'family', within the same system at any given time of year.
Here is an example of two types of Bok Choi... one doing real well (Joi Choi) despite the warmer temps and longer (finally) days, while the other (Mei Qing Choi...on the left) goes straight to bolting...
Luckily, I pretty much knew this to be the case from dirt gardening, so I planted much less of the Mei Qing at this time in the AP GH ...Here are the two in a DWC setting...even though the root zone temperature is somewhat lower than in the media beds...still, no dice with the Mei Qing Choi...Though notice the 'sea' of Joi Choi doing just fine, still in a veg state, behind the flowering and prone to be bitter-ish tasting Mei Qing below...
Knowing not only what to plant, and when, but what particular varieties to plant, in the season you hope to grow them in...could go a long ways in successfully rearing a particular crop to market... i.e. I'd have been totally fucked if I'd planted this cycles Bok Choi as Mei Quing instead of Joi.
Now, I believe as the weather gears on towards summer, that even the Joi Choi will become difficult to grow to full size heads without bolting being an issue. So I have a third even more heat tolerant variety already sprouted. Also, things like 'summer-fest' Komatsuna, or even Tatsoi might be more appropriate in the coming months (seedlings are doing well, so we'll see how those two fare in the heat of the early and mid-summer)...Neither are quite 'Bok Choi', but for a summer-time harvest of tasty Japanese brassicas, they're 'close enough for government work'
What's been working for you guys, in what set and setting?