Compost, animal manure, and peat moss not only improve the soil's moisture retention but they also attract worms that help water flow through the soil. If you're dealing with heavy clay soil, use a mixture of sand and organic material to reduce waterlogging.
I also suggest adding a pebble layer on top of pots to help keep moisture in the mix. For bagged soil, seal your bags well after use to keep the soil from getting dry. You can even add a little extra water to the mix and blend it by hand before sealing it. The ambient heat should help re-wet the mix.
The easiest way to re-wet dried out soil - in my experience - is just dumping it all into a bucket and pouring water and then mixing it up until the soil re-wets. If you pour too much water, just leave the bucket for a few days and the soil will dry out to a more normal moisture level.
Vermiculite, a natural mineral, has exceptional water-holding capacity and helps to improve soil moisture levels. Perlite, another commonly used inorganic additive, improves water drainage and aeration in the soil, preventing waterlogging and promoting healthy root development.
If the soil is hard because its dry and compacted, I would moisten the soil. Water it, let the water soak in, then water again, and repeat until the soil is deeply moist but not so much that water pools on the surface. Let it sit for a day. Any soil when moist is workable.
Refresh Old Potting Mix with New Ingredients
You can add pre-soaked coir (coconut husk fibre which helps retain moisture). I soak a compressed block in HOT water to speed up hydration and add liquid seaweed and molasses. Seaweed adds trace elements and both these ingredients feed soil microbes.
It may take an hour or more to thoroughly re-wet the soil. Be careful not to leave pots soaking in standing water continuously. Check them after an hour or two and remove them when they are hydrated.
How to Keep Soil Moist by Adding Compost. Compost can hold several times more moisture than dry soil particles. Adding compost to your soil allows the soil to hold onto more moisture, keeps precious microbiology alive (which helps plants thrive), and feeds your plant low amounts of plant food.
Dry soil can be easily improved by adding organic matter, such as well-rotted manure or garden compost. This will improve the soil structure and will help to retain moisture.
Key practices to improve moisture retention include planting cover crops, applying mulch, intercropping, increasing humus content with organic amendments, and modernizing drainage systems. These methods not only conserve water but also improve soil structure and health, leading to sustainable and productive farming.
Soil may also become hard due to lack of water, rocky composition, or excessive foot, equipment or vehicle traffic. Over-tilling, working soil when it is sodden, and mixing sand into clay soil in an effort to lighten it can all contribute to compaction, resulting in soil that is hard and difficult to work.
They act as a detergent to this waxy, impenetrable coating that surrounds your soil particles. Breaking down the waxy coating, soil wetters allow the water to reach your plants' roots, ensuring it gets the goodness that it needs. What do they look like? Soil wetters can come in granular or liquid form.
Use soil wetting products and organic matter
These products, available in granular, liquid concentrate or hose-on form, can dramatically improve water penetration. “Soil wetting agents help by penetrating through the waxy layer, enabling water to be absorbed throughout the soil,” she explains.
The addition of lime to garden soil can increase the alkalinity of acidic soil and add plant nutrients and minerals, creating a healthy lawn and a healthier base for plants to grow. Agricultural lime and dolomitic lime are two types of lime commonly used in lawns and gardens.
Compost is the best substance to mix in with hard soil.
Some other materials you can mix in include grass clippings, straw, manure, sphagnum moss, or leaf waste. If your soil has a lot of clay, mixing in some coarse sand can help improve the hard texture, too.
Add Water
For old and dry soil that isn't compacted, add water to a pot of soil and let it drain out from the bottom.
To dry out soil quickly, you can apply hydrated lime to the soil, add compost and then turn the soil thoroughly to aerate it. Adding hydrated lime and compost will help absorb the water in your soil, and turning it all will help distribute the water in the waterlogged soil throughout your garden.
But there are a few key differences. Vermiculite is better for water retention, that also means in that moisture it retains key nutrients for your plants and cuttings to soak up. Perlite works better to help drainage, this means its also better for loosening heavy, compacted soil.
Mulch helps retain soil moisture, decreases weeds, reduces erosion, helps cool plant roots, adds organic matter (provided organic mulch is used), increases the attractiveness of the landscape, and protects plants from adverse winter conditions.
Simply add organic debris to the soil surface and let your “underground herd” break it down. As it does, it will improve your soil's texture and make nutrients available to your plants. So don't be shy about applying copious amounts of organic residue to your soil.
Initially, just moisten the soil. Thereafter, water well once every week during the growing season then allow the plant to rest and breathe before watering again. If they're not too far gone, you may be able to rehydrate container plants. Plants stressed from drought should be fertilized carefully.
If the soil has dried out, it can be rehydrated by adding water. However, it's important to check for other signs that the soil might have gone bad, such as a sour smell or the presence of mold. Also, if the soil has been stored improperly or for a long period, pests might have infested it.