Merging hashes with values having the same key getting appended

I wanted to know what would be the best way to achieve this:

my_hash_1 = { fruits: { red: 'apple' }, vegetables: { green: 'spinach' } }

my_hash_2 = { fruits: { green: 'grapes' } }

expected_output = { fruits: { red: 'apple', green: 'grapes' }, vegetables: { green: 'spinach' } }

I have looked into using merge! but that gives me with output:

{:fruits=>{:green=>"grapes"}, :vegetables=>{:green=>"spinach"}}

my_hash_1 = { fruits: { red: 'apple' }, vegetables: { green: 'spinach' } }
my_hash_2 = { fruits: { green: 'grapes' } }
my_hash_3 = { fruits: { yellow: 'mango' },spice: { red: 'chilli' }}

# extended method (multiple hash)
def merge_hash(arr_of_hash)
    result = {}
    arr_of_hash.each do |_hash|
        _hash.each{ |k,v| result[k].nil? ? result[k] = v : result[k].merge!(v) }
    end
    result
end
puts merge_hash([my_hash_1,my_hash_2,my_hash_3])
# {:fruits=>{:red=>"apple", :green=>"grapes", :yellow=>"mango"}, :vegetables=>{:green=>"spinach"}, :spice=>{:red=>"chilli"}}