After receiving many pleas from growers for help with snails and slugs devouring their beautiful flowers and flower spikes, I decided to share with you the experiences and ways I have been fighting these nasty creatures of the night!
The dreaded snail, typically the brown garden snail (Helix aspersa) shown here, and the field slug (Deroceras reticulatum), are a nightmare every orchid grower wishes would go away.
These slimy creatures come out at night and totally destroy new growth like that new tender flower spike on your favorite orchid. Whenever I go out to the greenhouse and my husband hears a blood-curling scream, he just looks over to my mother and says "Uh-oh, snails!" They both know how I hate these creatures!
I will have to admit that snails and slugs cause 98% of the damage to my orchids. I am just devastated when I see a slimy film all over a plant and the new flower spike I have been waiting a full year for chewed right in half. Or when I see my prize Cattleya bloom all slimy and shredded like it had been through a rough storm. There is no mistaking the signs of a snail or slug attack.
Snails and slugs are mollusks belonging to the class of Gastropoda. After insects, they are largest class in the animal kingdom. The name means "stomach foot." Slugs, related to snails, do not have an external shell and do as much damage as their cousins. Gastropoda come in all sizes, shapes and colors. I am so "privileged" to have three types. I have the large brown garden snail (Helix aspersa). Also common snail is the small Oxychilus cellarium with a round, brown shell. If any of you know what this snail is please write me. Last is the dreaded common common field slug (Deroceras reticulatum).
All of these critters prowl by night eating everything in their site and then hide by day digesting their ill gotten gain! The slugs and the tiny snails crawl inside the pot moving through the loose medium making their daytime hideout at the bottom of the pot where you will never see them. They hide so well in the potting medium that you can look and look but never find them until you re-pot. Then you are surprised when you find them lurking in the bottom of the pot!
Controlling the seemingly endless hoard of snails and slugs is a continuing battle. I have yet to totally eradicate them from my garden and I still have them crawling around, but not as bad as in the past. Here are the best methods I have found to combat these slimy critters.
You can lure them to bait and destroy them. Beer I think most of us have tried this one and it is the favorite with the men... OK, this could be an opening but I won't go there... The method works best if you place the beer in a container just deep enough for the snails and slugs to drown in. Empty the container of dispatched critters every few days and replace with fresh beer for another go around. Yeast What, no beer? No problem. Mix a packet of yeast in a cup of water and place this mixture in your bowl. Fruit Cut citrus fruit such as lemons, oranges or grapefruit in half and place the halves cut side down on the ground. Leave your "offering" overnight where the critters can find them. In the morning, toss the fruit and the attracted snails you will find under the fruit into the garbage or put them where the birds can have breakfast. Potato Some slugs like potato. Take a big potato, cut it into two halves and place the pieces in suitable places, with the freshly cut surface downwards. In the morning collect the potato and critters for disposal. This "half potato method" is also good to bait several unwanted insects - try it! Dog food Do you nave a pet dog? If so, try dampened dry dog food. Place the food under a propped-up pie tin. Each morning, catch the snails hiding under the pie tin and destroy them or feed them to the birds.
Other non-toxic baits your can try include peanut butter, bran and sugar, celery sticks, and grated carrots.
You can trap the critters. A bit more costly solution is these cute turtle bait traps. I just sprinkle poison bait inside. The snails crawl inside and die. No muss, no fuss. Also, my real turtles who live in my garden can not get to the bait so they stay safe. Hunt them down one-by-one! Salt The bain of all snails and slugs. Go on a "slug hunt" armed with a flashlight and salt shaker. When you spot a critter, sprinkle them with the salt and watch the beast instantly dissolve! Although this method may be very entertaining to some people providing literally hours of amusement, it will have relatively little impact on the overall snail/slug population. Warning! Salt is also the bain to all orchids!! Do not shake salt on your plants or inside the pot on the medium! Be careful. Fight fire with fire The critters eat your plants, so it's fair to use critters that will eat them first! Natural predators is a good solution in some places. Ducks, chickens, or other poultry are great if you have a place to keep them in your yard.
Terrapins are great for a greenhouse. I have 6 turtles living year round in my greenhouse. All summer they hunt and eat any snail or slug they find crawling around. They hibernate in the winter so I look for other means during that time.
If you live where there are opossums, they love snails and will keep your yard clean if you allow them to visit and have lunch. The European Hedgehog is another little critter that likes to feed on snails. Make barriers Snails and slugs are very particular as to what they crawl across so there are many items you can use to block their path to your plants. Barriers must be complete to be effective. Any break in the wall will be found and used as a gateway to invade. Also, be sure the area being protected by a barrier is critter-free.
At the vary least, a good solid barrier will prevent additional critters from coming to dinner while you are combating those already feasting away on your plants. Copper Snails and slugs hate copper! Place your table legs on a copper plate, wrapping the legs and edges of the table in copper sheeting also works.
Snails and slugs are sensitive to the nitrate ion. The slime on their body reduces the nitrate ion to the toxic nitrite, which kills them. Place a nitrate barrier around every table leg in your growing area or form a ring around your plants outdoors. Several inorganic nitrates are used in the meat industry to improve the color of meat products (make it more red).
Ask around in pharmacies, etc. what types of inorganic nitrates are freely available to the public in your country. Ammonium nitrate found in certain fertilizers and available as baking powder is also an excellent source.
Snails and slugs are sensitive to getting dried out. A barrier of wood ash sprinkled on the ground will absorb the moisture from their bodies.
Other substances snails and slugs will may not cross with varying success include perlite, crushed oyster shells, pea gravel, coffee grounds, coarse sand, sawdust, bran, garden lime, diatomaceous earth, cayenne pepper, ground chili pepper or ginger and raw garlic slices. Of course all snails and slugs are different so experiment and see what works best where you live and grow your orchids. Chemical warfare, the last ditch defence.
Of course you can always use chemicals which I will not discuss in length in this article.
If you decide to use the baits, please read the instructions and warnings on the package before use. Birds, pets, animals, and your children can get very sick and even die if they eat some of the poisonous baits which are available. In open areas, place the toxic bait in special containers such as the turtle traps I use. Place the bait in secluded areas behind rocks and objects that are hard for your pets, children, and others to get at.
No single method will be completely 100% successful. Defend your plants using a combination of methods and most of all, be diligent. I hope this little bit of information will save a few of your flowers and flower spikes for you to enjoy.