Another option is not to waste your time on bid work. It is a very time consuming, highly competetive venture fraught with winks, nods and corner cutting. I think the odds of winning at blackjack are better then bidding a landscape install and winning. And even when you win you lose.
If you want to be a bid contractor you need to know people, have very good resources and understand the game (which does not seem to be the case).
I would also buy a lot of shirts (since you will be losing most of them)
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A much better business model is design/build rather than bid work.