My favorite method for dryness testing of larger containers is growing season-appropriate annual flowers in the containers. The annuals wilt when it is time to water. Choose annuals with flower colors appropriate for the bulb flowers, or seasonal vegetables if you don't use pesticides on the containers. Here in the winter, among my bulbs in large containers, I grow Escholtzia californica and E. mexicana (California and Mexican gold poppies), Linaria spp, Alyssum maritimum, radishes, various Chinese greens and other Brassica spp. Most of these reseed from year to year. After a number of years' weeding, there is nothing in those containers I don't want. Plus experience has shown some predator mammals may be deterred by some scented plants. Leo Martin Phoenix Arizona USA