The glasshouses do not currently meet the Government's sustainable development agenda and running costs eat up around £400,000 of RBGE budget every year. Ongoing maintenance is estimated to cost £250,000 for the next year.
Regius keeper of the RBGE Stephen Blackmore said he was not surprised by the government's decision to hold on capital projects, adding that it was "a very sensible thing to be doing" in the current economic climate.
He said: "We are not dropping our plans and I'm optimistic that in the long term it will happen, but we are much more strongly focused on seeing what comes along in terms of our operational costs - big capital projects can wait."
He continued: "With a big long-term project like this you are never quite sure when it will happen. It's a bit of a setback, but to be fair to ministers they are not cancelling anything here."
Commenting on the state of the current glasshouses, he said: "They were designed in days when fuel costs for heating were not a problem. We are hoping to be able to go ahead with the state-of-detail planning, ready to the point that if the Government were able to fund it, it's ready to go ahead."