Will tulip bulbs survive if I plant them in a boat in USDA zone 5? This boat sits in my front yard and I plant annuals in it every year. It was my mother's boat and holds sentimental value. I was not sure if the bulbs could survive during the winter.
I feel I should add some information about tulips. I live in the Pacific Northwest and a few years ago I went to the tulip festival in LaConner, Washington. I know a lot about plants but we had a Master Gardener leading our tour and I was blown away when she told us that tulips produce a toxin in the soil that reduces their own vigor slowly killing the bulbs of the tulips themselves!
For the tulip displays these tulip professionals plant in soil 2-4" deep in trays. This is so every single year they can fairly easily change the soil to grow luscious, vigorous tulips for the displays (which are mind-boggling beautiful). In the fields, they grow the bulbs one year and replant with something non-tulip. Once the tulip has grown in a soil once that soil should never be used to grow tulips again.
Weird, weird plant. For your house boat I would plant mass tulip bulbs in trays. Try to limit your colors/varieties to just a few for more bang for your buck. Don't plant in single rows. Replace the soil (POTTING SOIL ONLY!), replant the bulbs, cover with newspaper for the next spring.
If you think that is a lot of work, it is. Another great idea that I have seen on house boats is sedum also planted in trays. Don't have to do much except make dang sure you've got great drainage, don't ever overwater, fertilize very sparingly and every year you'll thank me, grin! Absolutely gorgeous! The colors keep changing and the fall is spectacular in color! What a great project! Have you seen what I am talking about? It became so popular most nurseries actually provide trays with a good selection of sedums that have already been successful. People use them as framed 'pictures' on outdoor walls as well as 'roof tops' on house boats.
Don't know if this could help, but, just as information, I have some tulips in plane ground, very deep, actually (after some years they were planted, some soil was added because of works to the garden; I believe that they are more then 50-70 cm deep, now). Some years ago, they survived to a very cold winter, during which temperature reached -24°C.