Eric,
I can agree with Dick about getting Jubs up to any decent stage.
I never had any problem germinating and getting the majority to 2-3 leaf stage.
But there is a continual attrition of numbers and now that my 10 remaining 5-6 YOA jubs [ about 10%]
have a base the size of a baseball, I dont want to lose any more
Now they are at this stage and still slow, I will be increasing he feeding rate to try to get them to accelerate.
After all that, I dont water them overhead at all. Only ever water the soil around them
Chris