The firm says garden centre prices have fallen by 10-15 per cent, meaning fewer people are selling up. But he said nursery prices were stronger.
Director Simon Quinton Smith said: "After the banking crisis, residential property values were the first to fall and they fell hard.
"Following hard on their heels, commercial property values also fell and other than in certain areas of the retail market, which continues to suffer badly, commercial values have started to rise.
"During this period, garden centre and horticultural property values remained static. They did not follow the trend of the majority of other property sectors.
"However, sometime during the second half of 2010, values started to fall and it appears they are continuing to fall, we believe mainly because of the difficulty purchasers have raising finance through lending institutions.
"In many instances we have had properties/businesses under offer two or three times that have fallen through for lack of finance.
"Current potential purchasers believe that they can get a deal and thus the offers that we are receiving are falling and continue to fall."