Now that you've sown your seeds, and have all these little happy seedlings growing, what can you do about not becoming a slave keeping the pots watered so your plants can grow, and eventually create the landscape of your dreams? I have had many successful years using what we call ‘Summer Watering Beds’. Using the minimal amount of materials, you can maximize your water efficiency, your time, and investment. First, you have to choose the right site. Any area that gets morning to noonday sun and afternoon shade is ideal. Now gather your supplies. Materials you will need are thick plastic sheeting (not tarps), a soaker hose (with the necessary valves if needed), level, straight edge, rake, hoe, enough mulch for the area, and organic fertilizers. Now you’re ready! Look at the number of pots you have, figure out the area space you will need to comfortably fit all those pots and then pace off. Choose the path of the least resistance because you are now going to level this area with the rake, hoe, and whatever tools you have on hand. You may need to discuss the possibility of removing turf with your spouse. Tiered beds work well too. The straight edge and level are invaluable now. You just have to dig down 5-7 cm. It’s important not to have a ‘deep end’. Remove any rocks from the floor of the bed. Use the soil/sod you removed to create a rim around the leveled area. Now lay down an even layer of mulch. The mulch can be shredded bark mulch, straw, hay or the like. Put down a layer deep enough to act as a cushion to prevent any stones from poking up and put holes in your plastic because this is the next step…lay down your plastic sheeting - Two continual layers are good, three layers are better. Don’t ever use plastic puzzle pieces for the first two layers, as your water will run out of the shallow pool. Avoid walking on the plastic. The plastic should be long enough to go over the rim of the leveled area like the bottom layer of pie pastry. Spread another even layer of mulch. This layer does several things that will be discussed later. Take your soaker hose and lay it atop the mulch. If the bed is small, a single run is all you need, but if the bed is large (10 m x 10 m like mine), use the entire soaker hose. Garden hose ‘T’s with shut off valves are great if you have more than one bed. Now turn on the water to fill the bed. Apply your organic fertilizer blend and with your feet work the fertilizer into the mulch. Make homogenized slurry as the water fills. The depth shouldn’t reach your ankles and the rim of the watering bed should be only an inch high as if the bed over fills, there is a spillway to prevent the bed from flooding. While walking around in the bed, note where the high spots are and check the rims. When filled, turn off the water and place your pots in the bed. Place water-loving plants, like Gunnera and Iris ensata, in deep spots and those that prefer dryer conditions, such as Sassafras, Rosmarinus and Iris douglasiana, on high spots. You can create one by mounding some mulch. One and two gallon nursery sized pots should just be sitting on the mulch with the water no deeper than 3 cm. Smaller pots should be sitting no more than 1 cm as not to drown tender roots.The best mulch I’ve used to date, in order, are hay, straw and cedar bark mulch. Cedar, you ask? Yep, cedar mulch has gotten a bad rap. My best performing native perennials grow in half composted cedar mulch. Because cedar is so nutrient poor it absorbs any nutrients in the soil locking it away, but the added nutrients also promotes decomposition thus allowing the nutrients to be slowly released as it composts. Fertilizer application total (both mineral and plant based) should be half a kilogram for every square meter of bed. It should balance out to something like 4-4-4 (if growing tomatoes or peppers, increase the potassium, phosphorous and calcium content). Throw in 1/4 more if you are using cedar. Chemical fertilizers are extremely fast release, will burn roots, and do not contain micronutrients vital for your seedlings (you wouldn’t feed your newborn junk food, right?) I use certified organic plant-based fertilizers. It’s hard to find certified organic soy, flax and cottonseed meal since it must certified organically grown, that means non-GMO seed. It’s a bit of a paradox to grow organically and use GMO plant meals. I use a half and half blend, by volume, of mineral fertilizer (greensand, langbeinite, and rock phosphate) and plant-based fertilizer (kelp and alfalfa meal). All mineral fertilizers take a little time before they begin to release their nutrients, but by the time the kelp and alfalfa have decomposed, nutrients locked in the minerals have started to leach from the matrix. Never use lime as this really messes up the soil pH of acid loving plants. The mulch does some important things. A few that spring to mind is that mulch: 1) Acts like sponge providing moisture over time reducing the amount to time normally used to water plants to a minimum while maximizing water usage;2) Protects the plastic sheeting from the sharp nibs often found on nursery pot bottoms. These put tiny holes in your plastic rendering your watering near useless;3) Cools the watering bed as the black plastic alone will reach root burning temperatures during the dog days of summer;4) Lets the roots coming out of the bottom of the pots have a medium to grow into;5) Great for growing tomatoes in 5 gallon pots as raised plants are kept off the ground, the main reservoir of the blight organism. Make a raised path for easy harvest;6) Plants love to be watered from below. Watering from the top may moisten the entire soil volume or the water runs out of the bottom and is lost;7) The mulch becomes lovely compost in year or two; and,8) Many more uses including growing purchased plants larger increasing transplanting success in the fall (it also allows you to plan the landscape).There are just a couple of rules to follow. One is not letting your plants wilt before watering. Wilting ruins vitality and robs valuable growing time. Some plants never recover from the stress. Tomatoes are liable to drop their flowers and newly set fruit. The second rule is no over watering, because if you let the water run and spill over, all dissolved nutrients will be lost. If you are going away on vacation, turn the lever on the soaker hose valve so you have a slow weep. The mulch should just be soggy. Check over the next few days and adjust the weep as needed. If you can convince a neighbor to come over to briefly turn on the water. You can repay them with tomatoes or turning on their soaker hose to their watering bed when they go on vacation! No matter how it’s done, you will still have live plants when you return, just keep in mind that larger beds, due to their seer volume, retain more water than smaller beds, so smaller beds require more water. I always make my beds large as somehow they are always filled by plant sale acquisitions. I transplant new plants into larger pots and at summer’s end the plants are healthy, vigorous and huge, just perfect for late fall transplanting!
When the autumn rains return, remove part of the soil rim to allow excess moisture to drain away. When cold temperatures arrive, plants cannot tolerate cold excessively wet soils as it increases the soil’s weight and leads to soil compaction…preventing oxygen from reaching the roots. Oxygen starved roots will die and the plant will suffer as a result. This leads to another topic of soil porosity in the soil/soil-less medium you use when potting up you plants or use as seeding medium. This is fodder for another article.