The trust is working with the HTA to find industry contacts to supply plants and hard landscaping. Both groups are also working on a plan for primary school gardens at the site.
Influence CLA is designing the landscape and the project has funding from Veolia. IBCC, in partnership with the University of Lincoln, has been awarded £3.1m from the Heritage Lottery Fund.
The Lincoln centre will include the Chadwick Centre, the Memorial Spire, the Bomber Command Archive and the 4ha International Peace Garden.
A floral bulb mosaic linked to the centre was planted outside Lincoln Cathedral on 25 September, with bulbs from JUB Holland. The mosiac will be unveiled on 21 April.
The first phase of the project is due to be completed by June, to coincide with the 70th anniversary of the end of World War Two. The gardens are due to open in June 2016.