Quite possible but not with Calabrese which ia long season sprouting broccoli. If you not willing to use insecticides, your next workable option is row covers. Flea beetles seldom do permanent damage, but the cbabage worms or cabbage loopers can destroy them quickly. Bt is my weapon of choice.
{{gwi:50219}}

farmerdilla: In your opinion does the damage I showed look like flea beetle or cabbage worm more? I'm not above using BT thought I haven't yet since I only witnessed one worm.

The damage at this point is consistent with warm or looper damage. But it it also consistant with the eating pattern of slugs, check for those also. Flea beetle damage consists of tiny holes like someone shot the plant witha shotgun. The photos don't show enough damage to be overly worried unless the infestation increase. no permanent damage done yet. The plants appear starved tho, You should probably feed them. They should be a blue green not a yellow green.

Just got done spraying with bt. How often should it be reapplied? After a rain I assume...

The only fert this bed has gotten is compost at the time of planting and liquid seaweed a couple of times (foliar spray once a week). I have Plant-tone and Foliage Pro (which I've been using on my containers) on hand. Any thoughts about which would be better for them? Or more compost?

Since you seem to be organic, Fish emulsion would be your best bet at this stage. Need something which acts quickly and has high nitrogen content. Composted Chicken manure incorporated into the soil in a ring around the plants would be long term fix.

I started hybrid broccoli on March 20th and planted out on April 13th- 16th. They are huge now. I am a bug for setting out broccoli and cauliflower while the plants are smaller than the garden center ones.

always take walks at night about 10 or 11 in my garden when things are young. Go with a flashlight and you will find slugs and earwigs....the two can really eat seedlings fast. If you are not into sqeezing them with your fingers take some forceps or tweezers. Be quick with the pincher bugs (earwigs) they move fast. By going out at night you can see how bad the problem is and just acouple nights might knock them back so you won't have to spray or use powders. Sometimes my wife joins me holding the flashlight for a romantic evening of bug squishing!!! That looks like snail or slug damage, visit your garden at night, its fun and revealing....

Since I just sprayed them with bt, should I wait a day or so before spraying with fert? In other words, will the fert wash off the bt?

I do indeed have slugs but they seem to prefer the moister end of the bed where the soaker hose enters. Easy to spot them, no need for stealth. I have not seen any earwigs yet this season. Last year they showed up after it had been consistently hot for a while. They liked to hide in the lettuce! Also, I have not noticed the tell-tale, um, leavings. Still think my problem is flea beetles and/or cabbage worms... Hopefully with the bt and some fert the broccoli will perk up.