I’ve ordered a 4L of Bud Boom by mistake and it’s too much. Wondering if this expires?

Hi Sylvette,

Thanks for your question. The Bud Boom will not expire but as in the case of most nutrients it could potentially lose it's strength over time so it's best to not wait too long to use it.

Can bud start and bud boom be used at the same time in week 6 of flowering ? If it' s not a good idea what should i be using for weeks 6 to 8 ?

We recommend using Bud Boom by itself during weeks 6-8 of flowering.

Would it be harmful to add through the whole flowering cycle?

Hello, thanks for the question.
I would advise not to use Bud Boom till you are at the week 4 of flowering at least. 
Feeding your plant Bud Boom prior to that may result in some issues.
If you have anymore questions please let me know
Thanks

The bottle I have sais "use during flushing stage" is that a typo?

Yes that is an typo. Our newer Bud Boom labels has been corrected. Sorry for the confusion. You should discontinue the use of Bud Boom when you start to flush with water in the last 1-2 weeks. 

should bud boom be used in conjunction with the bloom nutrient and at the end of the bloom cycle or during the flush period. As you are aware different strains have different bloom cycles.. All my plants are feminized and Autoflowering

Bud Boom should be used in conjunction with Holland Secret Bloom. We have incorporated both EC values in our feed schedule. First you will have to know how long your bloom cycle is for the strain you are growing. The last two weeks should be reserved for a flush with just water or a flushing agent like our Plant Flush product. Bud Boom should be used in the 2-3 weeks before this flush period. Please take a look at our feed schedule on our website for more information.