Bleach. For mixing the diluted bleach spray which makes long term plant survival much easier down here in the heat and humidity. My wife needs it for my white tee shirts I wear when gardening.
Metal conduit. For building my racks that support my strings that hold my tomato plants with those wonderful little clips that can be had for barely above a penny apiece.
Daconil and Copper fungicides for help keeping the foliage diseases at bay.
Cottonseed meal in the 50# bag. Great long term slow release fertilizer and it keeps the earthworms so happy in the garden.
Silicon grafting clips. Without them I would have probably stopped growing tomatoes in my blighted soil. Grafting has given me so much more flexibility in the varieties that I can now grow and enjoy.
Tomatoville. Where I have learned so much and enjoyed so many good discussions of gardening joys and woes.
Bill