Lining raised garden beds with liner material is an effective way to guard against airborne weed seeds invading your vegetables, as well as prevent harmful soil toxins from seeping into their medium.
Ideal compost materials would include those that break down and enrich the native soil as they decompose, such as:
Cardboard
Cardboard makes an excellent material to add the bottom of a raised garden bed, helping smother weeds while deterring Bermuda grass from taking over your plot. Plus, its decomposition will improve drainage and enrich soil nutrients! Combined with other organic materials like straw, woody material, leaves, pine needles, eggshells fish scraps or coffee grounds it creates an effective mulch bed in which plants can flourish!
Newspaper is another effective material to consider for garden beds. It will smother weeds while simultaneously improving drainage. As it decomposes, newspaper will enrich the soil as it breaks down. One thing to keep in mind with newspaper ink could contain toxic chemicals; look for sources using soy-based inks.
Raised garden beds can also be outfitted with carpets made of natural organic materials like jute or hemp to protect them from erosion and to chow down on weeds while still permitting water and deep roots to pass through freely; these durable materials should last through many seasons of construction before decomposing naturally over time.
If you prefer something more solid than cardboard and newspaper, old boards and lumber may make an excellent alternative material. Care must be taken not to use pressure-treated or glued lumber as this can leach chemicals into the soil and could leech more chemicals into decomposing wood layers as well as providing carbon and nitrogen benefits for soil health.
Newspaper
Newspaper is an effective choice for raising garden beds as it smothers weeds quickly while decomposing into rich compost quickly and cheaply. It is easily available from most grocery stores. Unfortunately, newspapers contain ink that could contain toxic chemicals; however, many newspaper companies have since switched over to soy-based inks as a more environmentally-friendly choice.
Hay or straw makes an excellent material to line the bottom of a raised garden bed, as it helps lock in moisture while adding organic matter and improving drainage. Straw works particularly well when planting vegetables that need lots of moisture such as tomatoes and beans.
Wood materials such as rotting hay, branches or twigs and small logs make an effective addition to a raised garden bed, though not as effective at choking out weeds as other materials on this list. However, wood provides nutrients to the soil through decomposition as it holds in moisture very effectively and can help prevent soil erosion while supporting healthy plant growth.
Leaves
If your property includes pine trees, use their needles in raised beds as mulch since they decompose quickly and compact easily – this method also works well when dealing with other leafy material in your yard.
Kitchen scraps and grass clippings can help aerate and enrich the soil, as well as improve its texture and structure. Woody material like branches or sticks should also be added at the base of your garden bed for increased carbon and nitrogen-rich nutrients, which will be released as they decompose over time.
Manure from farm animals like chickens, cows, pigs and horses makes for the best foundation of raised beds as it helps improve soil chemistry and provide nutrient rich organic matter for long-term gardening projects.
Landscape fabric is generally not recommended as a bottom layer in raised beds as it prevents soil erosion and promotes water retention, while keeping out weeds. However, if your crops require high protein or acidic environments (like legumes) then adding an additional layer may provide the results that you are after.
Pine Needles
Pine trees release needles at an incredible rate, often getting trapped under mulch and rocks and becoming difficult to rake out of lawns and gardens. While it might be tempting to use leaf blowers and pressure washers to clear away needles from beds or soil beneath, these methods could cause harm to plants in bed and damage the soil underneath them. Brooms work best or adhesive tape can even be used (adhesive side down). Gloves should always be worn while handling needles that could poke into your hand as this is likely. Sifters or compost bins can also separate needles from debris, with large piles near structures creating fire hazards.
Pine needles make an excellent base layer in raised beds to protect the soil from moisture fluctuations and improve drainage while also contributing nutrients as they decay. Furthermore, pine needles make a wonderful addition to compost when mixed with grass clippings, leaves, wood chips and other “brown” materials.
No matter whether you plan to plant from seeds or transplants, it is essential that a weed barrier be established on the bottom of your raised garden bed before adding soil. Materials like cardboard, newspaper, grass clippings and pine needles work effectively as weed barriers while adding “green” material such as coffee grounds or decomposing fruit/vegetable scraps will provide both carbon and nitrogen as they decompose over time.
Eggshells
Don’t throw away those crushed eggshells when planting a garden or feeding your chickens – use them instead to fuel plants, repel pests and improve soil health! Soak and grind to powder them as an organic fertilizer high in calcium for use on acidic soil – especially helpful when growing azaleas and rhododendrons that may burn in alkaline conditions.
Crumbled eggshells should be sprinkled around the base of plants that require extra protection, to deter slugs and cutworms by their sharp jagged edges acting as diatomaceous earth and cutting through their soft bodies. You could also add them to a compost pile where they’ll eventually decompose and add nutrients back into the soil over time.
When creating homemade compost, adding dry and crushed eggshells as part of your ingredients will contribute calcium, nitrogen and phosphorous, essential to its health and beneficial for its development.
If you are cultivating plants like tomatoes and peppers that require plenty of dietary calcium, such as mixing in eggshell powder into each planting hole will help prevent bloom end rot caused by low calcium levels in soil. It’s best to add eggshells both during autumn planting season as well as over the course of gardening season for maximum benefit.
Fish Scraps
If you have small amounts of leftover fish scraps that need to be used up, why not put them to good use in a raised bed garden? They help build the soil while providing essential nutrients, particularly nitrogen, to your garden. Beware however: spoilt fish can contain pathogens and parasites which could infiltrate edible plants and pose health risks to you and other gardeners.
As another effective weed prevention measure, use shredded or torn-up newspaper layers for weed prevention. They will suffocate any seeds that sprout as they assist other materials you lay down to work more effectively.
Organic carpets such as jute, cotton, or hemp can make great additions to the bottom of raised beds, successfully suppressing weeds while remaining permeable for water absorption and root development. But be wary of plastic carpets which don’t biodegrade and may leach chemicals that affect plant roots – organic carpets decompose over time while plastic may continue to leach chemicals that interfere with root development of vegetables in your raised bed garden.
Landscape fabric may be useful as a lining on a raised bed, but is not advised for vegetable gardening as it blocks earthworms and other beneficial soil-dwellers from passing through, compacts the soil, reduces air circulation and inhibits root development. If using it anyway, make sure not to step on it while walking through as this will further compact it – this could cause further compaction that harms plants. Hardware cloth would keep burrowing creatures at bay and is an alternative.
