Are you worried that your raised beds are drying out too quickly? Do you feel like your topsoil is too hard and crusty to plant seedlings or sow seeds into? I’ve had the same concerns about my soil in my first year of gardening, especially in the heat of summer. My autumn crops suffered because I didn’t take the necessary measures to better retain moisture in my soil.
When first creating your raised beds, you may not have the perfect conditions and access to the best soil, which can make them dry out. You can fix this problem by adding compost, which, aside from enriching the soil, acts like a sponge. Mulching and core gardening are also good options.
I’m not a soil scientist, but I’ve learned a thing or two from the gardeners I admire. I’ve also learned a lot from observing the soil from my own garden. While I added aged cow manure to my raised beds in the first year of gardening, it wasn’t good quality manure. It was most likely too old, and it dried out quickly.
The problem got even more obvious after harvesting the first crops in June. I didn’t have the resources to spread another layer of compost with my second plantings. Unfortunately, the soil dried out and I was left with a hard surface that repelled water.
This hydrophobic effect can occur if your soil is very well-drained, such as in raised beds or pots, because of heat, drought, and a lack of watering. Water can also run off because of poor soil structure, and perhaps excessive tilling.
I wasn’t inspired enough to mulch or resort to other methods, so my crops suffered. But there are plenty of things you could do to fix this issue.
Add a generous amount of compost to help retain moisture
It seems like compost is the answer to everything: it provides nutritients, suppresses weeds and keeps our raised beds from drying out. It’s true, compost really is a miracle ingredient in gardening, so don’t be afraid to make your own.
Compost is a fluffy, organic material that is the product of aerobic bacterial decay of nitrogen and carbon from animal manures, leaves, woodchips, cardboard, and plant material. Because of its aerated structure and organic composition, it can hold a lot of water. Studies show that a 3-inch compost layer can increase the water retention of droughty soils 2.5 times, provided that it’s watered enough for a minimum of 7 days.
If your raised beds look like they have a hard, dry surface, run a hoer through the top couple of inches of the soil. This will break it up and make it more permeable. Next, apply a minimum layer of 3 inches of quality compost on top, although 6 inches would be even better if your garden is new.
Make sure your compost is soft, fluffy, and moist, and that it comes from a trustworthy source. Water everything thoroughly. Ideally, you should water the raised bed slowly if you have access to drip water irrigation. If not, you need to water your raised beds daily until they reach the optimal level of hydration.
You can incorporate compost in the top 6 inches of your soil for faster results in the first year, but the purpose of no-dig gardening is to disturb the soil as little as possible. The key here is patience. You won’t miraculously improve your soil in one year – soil building takes time. If you do this every year, however, your topsoil will soon be mostly made up of compost, which will mean much less watering in the long term.
PROS: If you have access to large quantities of compost, adding a 6-inch layer will benefit most seedlings and plants without the need of doing anything else to your soil. You can create new beds on top of whatever soil you have by just adding cardboard to suppress weeds and compost.
CONS: Compost can be expensive and/or unavailable. If you can only use a little bit at a time or decide to make your own, it will take a while before the soil starts becoming more fertile and workable. Using mulch may be a better alternative for you.
Mulch with organic material, especially in hot summer months
Mulching heavily isn’t suited for areas that get a lot of rain because it creates the perfect environment for slugs and snails, but if your problem is beds that dry out too quickly, mulching will be a key ingredient for preventing water evaporation.
Many gardeners make the mistake of adding mulch on top of compacted, dry soil without amending it first. Mulching alone won’t save your garden unless you do it repeatedly over the years. It’s preferable that you use a good amount of compost and only apply a layer of mulch on top.
You can use all kinds of organic materials as mulch, and you probably even have them in the garden: grass clippings and leaves are a good option. Straw has been traditionally used in permaculture, and wood chips may be an option, but they can be acidic and they decay much slower.
I have rainy springs and hot, dry summers, so mulch isn’t always the best option for me. I’d much rather use compost alone as a mulch, but sometimes, I need some extra protection for the soil so I can water less and keep the plants cool.
However, I still mulch, especially around my thirsty plants (tomatoes, peppers, eggplants), but because of my climate I only apply mulch in late spring, and I don’t add it to all my raised beds.
You can combine both these methods: rely on compost for most of the year and reach for straw or other types of mulches in the hot summer months.
PROS: Mulch can be anything that covers the soil surface and keeps moisture in. Organic mulch like grass clippings and leaves is easily available and free. Straw is the best option, though.
CONS: In rainy climates, mulch can be the perfect hiding place for slugs and snails, so you should consider this when using it. In countries where mulching isn’t popular, wood chips are sometimes hard to find, or very expensive.
Use the core gardening method as a smart way to keep water in
The core gardening method is essentially digging a trench in your raised bed every spring and filling it with wood logs, bark, cardboard, straw and other water-absorbing organic material. This organic ‘core’ will decay over time, but until it does, it will hold on to the perfect amount of water.
This will significantly reduce the need for watering throughout the year, and it’s a cheap and easy method of ensuring a sponge-like water reservoir inside your raised beds.
Core gardening isn’t new, in fact, it’s been around for centuries in places where there isn’t much rain, like the Middle East. You can also find this principle in a slightly different method called Hügelkultur, which is a German soil-building method.
Hügelkultur is a technique gardeners use to build mounds of soil with a core of rotting wood. Some people recreate this principle in their raised beds, but you need to have very deep or high edges to your raised beds to be able to do that.
PROS: The core method and Hügelkultur can be lifesavers in dry areas and they’re free to make. For Hügelkultur, it’s a one-time investment of your time and all the rotting wood you can find. Core gardening, however, requires that you repeatedly refresh the core, so you can change your mind if it doesn’t work for you.
CONS: Core gardening goes against the principles of the no-dig method, as it disturbs the soil. Hügelkultur is amazing, but you need to create your raised beds in such a way that you can have the necessary depth.
Conclusion
You probably noticed that I haven’t included any tips for watering your dry raised beds to make them more hydrated.
While your plants might appreciate watering, and buried terracotta pots or drip irrigation are certainly helpful, they are not the answer. That’s because no matter how hard you try to keep on top of watering, as long as you don’t have a good soil structure, water will just run off.
If your first raised garden beds have very poor soil, sometimes it’s best to just start over. Empty the contents of your raised beds and add good soil and compost. If you don’t have the resources to do that, adding as much organic matter as possible will always be a good idea. Compost and mulch will improve your soil structure over time.
