Food-stores and cafes are few and far between in rural Finland, so trekkers should stock up well with food supplies. In many areas petrol stations and newspaper kiosks sell quite a wide range of groceries. Try to choose products that won't leave you with lots of waste packaging (see the page on Litter and How to make sure you leave no trace).
In most cases, the water in springs and wells is clean and safe to drink, but lake-water may contain harmful algae or bacteria from animal droppings. Spring water usually is drinkable even if it is not examined. In Southern Finland and close inhabited places the spring water may be spoiled. Wells are provided for visitors in many popular areas. To be on the safe side, many Finnish hikers still boil all their drinking water. The use of natural water is at your own risk.
Portable camping stoves can be useful, especially on longer trips. Campfires may only be lit with the landowner's permission, or in the special public campfire sites and cooking shelters in many national parks and other popular areas, where firewood is provided free of charge.
Wild berries and mushrooms can be freely picked, even on private land, but they should be carefully identified, as some varieties are poisonous. Other pickers can be asked for advice, but it is considered impolite to gather mushrooms or berries too near other people.
During a hiking trip, it is important to pay attention to wild animals that might be interested in your food supplies. It is not wise to leave any food out in the open for long periods of time, since the aroma draws the attention of for example small rodents. When staying overnight at a wilderness hut, it is recommended not to leave your backpack on the floor or leave behind any sort of food supplies to avoid luring rodents inside a hut. It is possible to hang your backpack above the ground at some of the equipped campfires, where there are special hooks installed on the sides of woodsheds. If a rodent, for example a mole, has been in touch with your food supply, do not eat the food. It is not recommended to leave any food or food scraps behind at a campfire or other camping spots, since it might also attract wasps.