This article was published in err a couple of weeks ago, and is being republished today as a corrective measure. Apologies. -Ed.
Back in a June post[i], I referenced the Ontario Native Plant Council’s best management practices for Alliaria petiolata (Garlic Mustard).[ii] In it they referred to certain native plants that can be used to outcompete it. I would like to mention one other that I am fond of having in my garden. Packera aurea (Golden Groundsel) has a diminutive orange inflorescence and is native to the Peterborough area. It can be aggressive as it reproduces through rhizomes and adventitious shoots on the stems. It is better situated in moist soils and so it may be more subdued in a drier location. In her blog, The Humane Gardener[iii], Nancy Lawson discovered that when she inserted clumps of Golden Groundsel into patches of Garlic Mustard, the latter quickly became surrounded. Garlic Mustard is known to be allelopathic and inhibits the growth of some plants. However, Golden Groundsel does not appear to be inhibited by it.
Golden groundsel, Packera aurea
Anemonastrum canadense (Canada Anemone) is a beautiful vigorous native ground cover that performs well in sun to shaded environments; although it can develop brown leaves in more arid conditions. I am using it to limit the advance of Campanula rapunculoides (Creeping Bellflower). The intent is to envelope it so that it is unable to photosynthesize, grow more foliage, and store energy in its roots. One might argue that this is simply a matter of replacing one problem with another. While it is true that Canada Anemone can be overwhelming, it may be limited by deadheading the flowers, removing rhizomes, adding mulches, and by installing edging below the soil surface. As a native plant, it supports pollinators such as miner bees, sweat bees, and hover flies. The Xerces Society notes that it supports “conservation biological control.”[iv] This is a plant that attracts beneficial insects to your garden which in turn will help control other insects that damage your other plants.
So far, the Creeping Bellflower’s development has been slowed but there are still some basal leaves within the patch and at the perimeter. Right now, it is still a team effort: Canada Anemone and me.
This article was published in err a couple of weeks ago, and is being republished today as a corrective measure. Apologies. -Ed.
Back in a June post[i], I referenced the Ontario Native Plant Council’s best management practices for Alliaria petiolata (Garlic Mustard).[ii] In it they referred to certain native plants that can be used to outcompete it. I would like to mention one other that I am fond of having in my garden. Packera aurea (Golden Groundsel) has a diminutive orange inflorescence and is native to the Peterborough area. It can be aggressive as it reproduces through rhizomes and adventitious shoots on the stems. It is better situated in moist soils and so it may be more subdued in a drier location. In her blog, The Humane Gardener[iii], Nancy Lawson discovered that when she inserted clumps of Golden Groundsel into patches of Garlic Mustard, the latter quickly became surrounded. Garlic Mustard is known to be allelopathic and inhibits the growth of some plants. However, Golden Groundsel does not appear to be inhibited by it.
Golden groundsel, Packera aurea
Anemonastrum canadense (Canada Anemone) is a beautiful vigorous native ground cover that performs well in sun to shaded environments; although it can develop brown leaves in more arid conditions. I am using it to limit the advance of Campanula rapunculoides (Creeping Bellflower). The intent is to envelope it so that it is unable to photosynthesize, grow more foliage, and store energy in its roots. One might argue that this is simply a matter of replacing one problem with another. While it is true that Canada Anemone can be overwhelming, it may be limited by deadheading the flowers, removing rhizomes, adding mulches, and by installing edging below the soil surface. As a native plant, it supports pollinators such as miner bees, sweat bees, and hover flies. The Xerces Society notes that it supports “conservation biological control.”[iv] This is a plant that attracts beneficial insects to your garden which in turn will help control other insects that damage your other plants.
So far, the Creeping Bellflower’s development has been slowed but there are still some basal leaves within the patch and at the perimeter. Right now, it is still a team effort: Canada Anemone and me.
Photosynthesis is the process by which plants use sunlight, water, and carbon dioxide to create oxygen and energy in the form of sugar. Plant leaves are most often green because that colour is the part of sunlight reflected by a pigment in the leaves called chlorophyll. However, not all plants are completely green!
Variegated plants can be a beautiful and unique-looking addition to your plant collection. Variegation simply means that the plant’s leaves have both green and non-green parts. Some have shades of cream, or yellow, light green, pink, purple, or red – to name a few. Some plants have a stark white variegation that makes these plants really stand out. Many times, these plants are used to brighten up shady, dim areas or as used as focal points in landscapes or as striking indoor plants. Variegated plants can be the result of engineered breeding or a grower taking advantage of some type of random genetic flaw (chimera).
Leaves of variegated plants occasionally lose their colorful markings and return to plain green. This twist of nature can be frustrating when extra money is spent for the unique foliage markings. Variegated plants often have smaller leaves and are less vigorous than green specimens because the lack of the green pigment means less chlorophyll for generating energy.
Variegated plants can revert or turn green beginning on a stem, branch, or another area. Reverting back to solid green leaves could be a protective way that the plant returns itself back to a healthier form. When this happens, the best thing to do is prune out the affected leaves because if you don’t, the plain green can actually take over the plant because of the increased chlorophyll and vigour as compared to the variegated foliage. If the reversion continues, try to provide your plant with some extra light by moving it to a sunnier location if possible.
The hosta in this picture shows great variegation in all leaves except one. That leaf should be removed to preserve the variegation.
Garden gazing out the window a couple of weeks ago I noticed, with a sickening jolt, that my Clematis x jouiniana ‘Mrs. Robert Brydon’ was wilting. (It’s only a plant, Lois, only a plant). She has been in my garden for 4 years and had been growing very well up to this point but it appeared she must have clematis wilt. Clematis wilt and clematis slime flux are the two diseases that this particular cultivar may be susceptible to. Not noticing any slimy, smelly matter oozing from the stems, I ruled out slime flux.
‘Mrs. Roberty Brydon’ showing leaf wilt
According to Missouri Botanical Garden, clematis wilt is a serious disease of clematis caused by the fungus Ascochyta clematidina. This fungus can survive in the soil surrounding infected plants and may overwinter in infected plant debris. The fungus appears to be activated by ‘high humidity and favourable growing conditions found early in summer’. Any to all stems may be affected and the whole plant killed down to just below soil level. The good news is that the plant may recover after a year or two.
There are ways to manage and avoid having your clematis plants affected by this disease and indeed other diseases of clematis. Strategies (cultural practices) include a favourable planting site with 6 or more hours of sun. Soil should be fertile and well-drained with good air circulation around the plant. The area around your clematis should be free of plant debris and avoid any injury to stem and roots. Do not cultivate the soil around your clematis plants and mulch it well. Water carefully, keeping water off the leaves. If your plant becomes infected, cut the diseased stems just below ground level and destroy them.
‘Mrs. Robert Brydon’ in flower
I removed and destroyed all the diseased growth on my clematis (which was all the growth) and there is now new growth coming up from the root. I will be paying attention to keeping leaf debris cleaned up, improving air circulation around the vine and watering as needed, with care.
Hopefully ‘Mrs. Robert Brydon’ will survive this setback. Her profuse, pale blue flowers are unusual and appealing to me. The gardener, Robert Brydon, who ‘found’ this clematis in a Cleveland, Ohio garden in 1935, clearly thought enough of it to name it after his wife! Sigh.
It is early May and my husband has been watching the rhubarb emerging with great anticipation. I like rhubarb, he loves rhubarb and it will soon be time to start harvesting the stalks (petioles)!
Rhubarb (Rheum rhabarbarum), native to central Asia,is an easy, hardy, and edible perennial. Technically a vegetable but treated as a fruit, it is long-lived, easy to care for and bothered by few pests and diseases.
Rhubarb is sold by ‘crowns’ or perhaps you can get a division of a plant from another gardener. Spring and early fall are the best times to plant it. Rhubarb likes a well-drained site with full sun (6-8 hours minimum). Give your plant plenty of space to grow, about 3m2. Rhubarb is a heavy feeder so mulch around your new or established plant with compost or well-rotted manure. I generally give mine a spring dressing of compost as it starts to emerge in the spring. Rhubarb should be watered deeply during times of drought.
A new rhubarb plant will need a couple of years to get established before you start harvesting it. Don’t harvest any stalks the first year and then very little the second year. The plant needs those large leaves to develop to provide energy for the roots and crown to grow. Over the growing season, flower stalks will start appearing and these should be cut off at the base to reserve energy for the plant.
Rhubarb is ready to harvest when the stalks are 25 – 40 cm long. Grab the stalk part way down and pull or twist to the side. When I pull rhubarb, I come prepared with a paring knife and cut off the leaves after pulling the stalks and leave them as mulch. Rhubarb leaves are toxic as they have high levels of oxalic acid, however they can be safely composted.
Rhubarb is a cool weather plant so as the season warms up growth may slow down. Let your plant rest so the crown can recover. If you have an established plant that doesn’t seem to be as vigorous as it was, it may need division which should be done in early spring. Dig up the whole plant if possible. Rhubarb has a very deep tap root but if you capture enough, you can divide the plant making sure each division as at least one or two buds. Plant your divisions with the buds 4 – 5cm deep, gently firming the soil.
The only other job to do is weed through all the tempting rhubarb recipes. Enjoy!
I appreciate a well made garden tool; the way it feels in your hand and the way it works. Over the years, I have acquired many tools but not all are winners. As time has passed and my needs have changed, some of my favorites have been displaced by newcomers. With the coming season, I thought I would share some of my favourites.
The tool that is by my side constantly is my hori-hori knife, a one handed multipurpose tool, used for digging and cutting. It has a long steel blade that is smooth on one side and serrated on the other. The serrated edge is handy for cutting through roots and difficult weeds and the smooth side is more appropriate to delicate cutting tasks. The tool originates from Japan, where it has been used for centuries to remove vegetables and Sanasi plants from the mountains. The word ‘hori’ literally means ‘to dig’ in Japanese.
The point of the blade enables you to dig rows for seeds, seedlings, and holes for larger plants. There is a built-in ruler, which consists of notches on the blade. When not in use, the knife hangs in its scabbard on a hook in the mudroom where it is readily accessed before going outside.
Spring cleanup highlights the need for pruning shears or secateurs; a type of scissors for use on plants. I prefer bypass pruners as they make an accurate and clean cut. I have used Felco pruners for many years and found them to be sturdy, they have replaceable parts (including the blade) and are available in many styles. I use the Felco 12 and Felco 6 which are suitable for people with smaller hands. For woody plants that are too thick for pruners, I switch to loppers which are long handled two handed pruners. My flower shears are small needle-nosed pruners that can get into tight places while delivering a clean cut to the stem.
The spade that gets the most use is my rabbiting spade which was originally designed for digging out rabbit burrows. The blade is very long, curved and tapers towards the end. It is ideal when working in confined spaces or for transplanting plants and shrubs. It has a short handle and a classic YD handle.
For working on woody plants with a diameter larger than 2 inches, I turn to my Japanese pruning saw. Light weight with an ergonomic handle that helps to prevent wrist fatigue, its tooth size and geometry are chosen for cutting green and wet wood, ie, live wood. These saws cut on the pull stroke, which keeps the blade straight which I find makes it easier to use. It makes fast work of any task leaving a very clean cut. The saws are available in a number of sizes and types. I prefer to buy brands where the blade can be replaced when needed. I use mine for everything from foraging for evergreens at Christmas to dealing with invasive trees and shrubs on the farm.
One of my first purchases was my Haws 9 litre watering can. First designed in 1884 and virtually unchanged to this day, it is made from painted galvanized steel that is meant to last lifetime. It has an extra long spout and comes with a removable oval brass rose. The Haws is well balanced, making it easy to carry and tip. When I do need to water plants, I do it by hand using the Haws and water at the base of the plant directly from the spout. It is quite accurate due to its balance.
From the oldest to the newest, meet my new broadfork, a tool that allows you to aerate your soil while preserving soil structure and microbial populations. Broadforks have two pole handles connected to a row of steel tines along a crossbar, which permits you to use your body weight to drive the tines into the ground while holding the grips. The tines loosen the soil to a significant depth. Pulling the handles allows you to crack to soil slightly creating passages that allow air, water, and nutrients to reach deep into the ground and create a better growing environment. All this with no bending!!
“Tools of many kinds and well chosen, are one of the joys of a garden” ~ Liberty Hyde Bailey
Dry soil with little nutrient value; amended soil with many nutrients
As we approach the reawakening of our spring gardens, I thought it would be a good idea to review the importance of soil maintenance.
How you prepare your soil will have huge implications on the health and survival of all your plants. Two years ago, my husband dug a deep hole in preparation for building a small pond. All the clay, rocky soil was removed. In the end, we decided on a smaller water feature, so I filled the hole with what was left in my two compost bins and backfilled with some of the clay that had been dug up. I hadn’t tested the soil, but through the use of good quality compost, I ended up creating a garden bed that was rich in nutrients and a soil that had good water-holding capabilities. The following spring, I decided to plant annuals in my ‘new’ garden bed. They were fantastic! All plants in this particular area of the garden flourish! The old saying, “Tend the soil, not the plants” is right on the mark!
My late summer garden with zinnias & cosmos
A well-fed soil will produce healthy and beautiful plants. It provides a physical anchorage, water, and nutrients and allows the exchange of gasses between plant roots and the atmosphere. The ideal soil is made up of 50% solids (mineral and organic materials) and 50% pore spaces (air and water). Water is best at 20-30%, air at 20-30%, mineral at 45%, and organic at 5%. These proportions can and do change dramatically in response to climate and rainfall.
There are 3 types of soil that most of us are familiar with; clay, silt and sand.
Clay is tiny particles about the same size as bacteria. Silt’s particles are 10 times larger than clay. Sand particles are 10 times larger than silt. The larger the particles, the easier it is for water to penetrate. I have lived with both sand and clay soils, and each have their own challenges.
Soil is full of living things like decaying organic matter, microbes, bacteria, fungi and microorganisms. It is very much alive! The world is depleting its soil at a much faster rate than the soil is able to replenish itself. One inch of topsoil that is lost due to erosion, wind or farming takes many, many years to replace.
There are more organisms living in one teaspoon of soil than there are people on this earth. Think about that! Soil is so very important and many of us are not aware of the benefits of keeping our soils healthy!
Here are a few ideas.
MULCHING
Mulching can greatly benefit the health of your plants. Some of those benefits include:
Improving the nutrient content over time of the soil (depending on the type of mulch used)
Reduces weeding as it often smothers them
Reduces water evaporation, therefore less watering is required
Protects the soil from temperature fluctuations, therefore avoiding the freeze/thaw cycle
Prevents soil compaction and reduces soil erosion
There are many materials available to be used as mulches in the spring. Refrain from using black or red coloured mulch. I prefer a natural cedar mulch.
DIVERSIFY AND PLANT MORE NATIVES
We are stewards of our land, no matter how small of an area we own. Native plants have evolved over thousands of years and because they have adapted to their environment, they are easy to grow, provide habitat and food to a variety of insects and wildlife, are remarkably resistant to disease and are generally tolerant of many soil conditions. The majority of native plants have very long root systems which work to improve the structure of the soil.
Doug Tallamy, author of Nature’s Best Hope, speaks about the decline in wildlife populations because of the disappearance of the many native plants they depend upon. He would like us to turn all our yards into what he calls our own Home Grown National Park. This would create corridors of conservation for all the wildlife, insects and birds. Take some of the grassy area you have and create a new pollinator garden with some local native plants. You will be amazed at the wildlife you will see!
BUILD UP YOUR SOIL WITH LOTS OF ORGANIC MATTER
Soil improvement can be a long process. It is recommended that you add a yearly application of organic matter, preferably in early spring. Do not be tempted to dig it in. Weed seeds can lay dormant for many years and as soon as they are disturbed and see the light, they will begin to grow. Lay the organic matter on top of your beds and the worms will do the work.
Use shredded leaves in the fall. I shred my leaves, rake them on my garden beds and leave them over the winter. Come the spring, the worms will do the job of taking them down into the soil.
Manure, Triple Mix or Compost from a reputable Landscape Supply Store
CONSIDER LASAGNA GARDENING
Consider creating new garden beds without removing turf by first covering it with newspaper or cardboard and then layers of soil and compost. If you do this in the fall, you will have a brand ‘new’ garden bed that you can plant in come the following spring!
My new garden bed; compost/leaves on top of cardboard and left to decompose over the winter!
PLANT COVER CROPS
Bare soils encourage erosion, loss of nitrogen, growth of weeds, water accumulation and spring runoff. Cover crops create a universe of microbes, mycorrhizae, fungi, and bacteria. By planting a cover crop in your vegetable garden in the fall, you will receive many benefits such as reducing water run-off, restoring carbon to the soil, erosion prevention and pest and disease resistance. Some of the more common cover crops that are used are legumes such as clover, beans and peas and grasses such as ryegrass or oats. Plants in the legume family take nitrogen gas from the air and convert it to a form that plants can use. In the spring, turn the dead material into the soil.
Well, yes … I am, but I have a plan. February 28-March 4/22 is National Invasive Species Awareness Week. This is an international event whose purpose is to raise the awareness of invasive species. “Invasive terrestrial plants in a forest ecosystem can be trees, shrubs, or herbaceous plants that have been moved from their native habitat to an introduced area where they are able to reproduce quickly and crowd out native species. These plants are introduced and spread by infested packaging material, seed dispersal by both environmental and human sources, or by escaping from gardens.” Also look at Ontario’s Invading Species Awareness Program for more information.
Biodiversity is essential to the continued healthy life of an ecosystem. Invasive plants can quickly destroy it and humans require the natural resources found in a healthy ecosystem. We need food and we need water to survive. We are a part of the ecosystem too. Doug Tallamy says it best in his book, “Bringing Nature Home” where he writes “…ecosystems with more species function with more efficiency, are better able to withstand disturbances, are more productive, and can repel alien invasions better than ecosystems with fewer species.”
I became aware of invasive species about 15 years ago when on my walk to work, I noticed some English ivy (Hedera helix) growing in a small wooded area. Then, I realized that English ivy had totally carpeted that area. There were no other plants! A couple of years later, I saw the same thing but this time, it was a larger forested area and the culprit was goutweed (Aegopodium podagraria). Since then I have read more about invasive plants and, sadly, now often see problem areas.
So, back to my plan. I was aware of some of the invasive herbaceous perennials so had steered away from them. See terrestrial plants and aquatic plants for more information. However, my husband and I are tree lovers and have a rural property so we frequently indulge in purchasing new trees to add to our collection. Unfortunately, we ended up with two Norway maple (Acer platanoides) trees, two burning bush (Euonymus alatus) and a barberry (Berberis thunbergii) shrub. This year, I plan to convince my husband that they must go. I would like to replace the trees with two red maple (Acer rubrum) or perhaps a couple of sugar maple ((Acer saccharum). The burning bush will be replaced by a couple of native viburnum maybe nannyberry (Viburnum lentago) and the barberry, well, it will be replaced by a native bush honeysuckle (Diervilla lonicera). See Southern Ontario Grow me Instead Beautiful Non-invasive Plants for Your Garden. This is a great resource. It includes some native and some non-native plants to include in your garden plans.
I am inspired to be a better gardener every time I write a blog for the Peterborough & Area Master Gardeners. I hope that you will have a look at some of the links above and below and be inspired too. Please only use non-invasives in your gardening plans this year.
A new group on Facebook is the Canadian Coalition for Invasive Plant Regulations. The group is very concerned about the spread of invasive plants in Canada and would like to do something about it.
Many will be receiving a beautiful bouquet of flowers today in celebration of Valentine’s Day. If you are one of the lucky ones who has a sweetheart who will bring you flowers,here are some tips to help you keep your Valentine flowers fresher longer.
Cut flowers need food in the form of carbohydrates or sugar to last for one to two weeks in your home. They also need citric acid to get the pH level correct allowing the stems to draw up water. It has been scientifically proven that water travels faster through the xylem (tissues that carry water through the plant) when the pH is around 3.5. Flowers also need to keep their stems clear of bacteria that can clog and prevent the uptake of water. This can be addressed with bleach. When you add the small package of floral preservative you receive with your bouquet you are giving your flowers the food, pH level and bacterial killing agent they need to stay fresh longer. You don’t necessarily have to use the entire package. Save some to add when you need to refresh your arrangement. You can also buy floral preservative if you bring in flowers from your own garden. Home remedies using vodka, aspirin, pennies or bleach may work, but the little package you get with your bouquet is effective and easy. One good home remedy is 1 tsp. of bleach and 1 tsp. of sugar in 1 litre of water.
When you get your flowers, unwrap them as soon as possible and get them into water.
Use a clean vase filled with warm or room temperature water. If you have hard water, let it sit for 24 hours before using. Add your preservative and mix until dissolved.
Using a sharp knife or pair of scissors or pruners, cut stems under warm running water and place immediately into the vase. Cutting stems on an angle will give more surface for stems to draw water and the stems won’t lay flat on the bottom of the vase cutting off that ability.
Remove any leaves that will go below the water line. These will rot and can cause bacterial problems.
Keep your flowers out of direct sunlight and in a cooler rather than warmer room.
Keep the water topped up daily. Your flowers will drink if they are happy.
You may find that flowers wilt or droop. If this happens, re-cut the stems at least half an inch and move to another clean prepared vase. I suggest that you remember this when you do your first cut on your flowers and keep the stems longer, so you are able to re-cut and move your bouquet to smaller and shorter vases a few times before they are totally spent.
Some types of flowers will last longer than others, so if you have a mixed bouquet, you will probably lose some blooms before others. Zinnia, carnations, larkspur and glads all should last longer than two weeks.
One of our Peterborough Master Gardeners wrote a great article last summer on growing and harvesting flowers for cutting. For that article go to Reaping the Flower Harvest.
The reason we love fresh flowers is they are with us for only a short time. Accept that fact and enjoy your bouquet!
It is that time of year where we turn our attention to thoughts of what we would like to grow in the coming season. Because of the pandemic, many of us have dabbled in sowing some seeds indoors. It does require time, space, proper lighting and the patience to check your seedlings every few days for proper moisture levels or any signs of disease.
Author’s Seed Catalogues for 2022
Begin planning your garden early. Now is a good time to browse through the seed catalogues and decide what crops you want to grow based on your own likes and dislikes, as well as how much of each you will need.
If you don’t have the time or desire to start seedlings indoors, there are many vegetables that can be seeded outdoors in the very early spring. They are known as cool season crops.
I look forward to getting out into my garden in the early spring, however, we should not start digging too soon as there are many beneficial insects and native bees that overwinter in the soil or under leaf litter. They all need time to emerge from their long winter nap. By growing cool season crops, I get to play in my garden early and benefit from a good supply of fresh vegetables.
Courtesy of Pixabay.com
All the following vegetables can be seeded outdoors as soon as the soil is workable.
LETTUCE & GREENS
There are so many varieties of salad greens such as leaf, mustard, arugula and mesclun. Lettuce is generally a cool season plant, but newer varieties have been developed that will grow happily in the summer. Salad greens can bolt quickly when the weather gets really warm, however, there are varieties that are more bolt tolerant. I usually choose seed that I can sow early in the season. These particular varieties can withstand some shade in the summer so I plant the seed behind a larger vegetable such as kale so that they get the protection they need from the hot sun. Be sure to check the seed package to understand when to sow, how to harvest, and how quickly the lettuce will bolt.
CARROT
Carrots need good drainage and work very well in raised beds. They work best when planted as soon as the soil can be worked. They require plenty of sun. The cultivated carrot originated in Afghanistan and was purple. According to William Dam Seeds, they believe the orange carrot was developed around the 16th Century. There are many different varieties and some of my favourites are the Nantes and I had great success last year with Nantes Napoli.
KALE
I find Kale a very easy vegetable to grow and it will last well into the fall. It likes well drained soil. It is best to harvest the young leaves as the older leaves will get quite tough and stringy. It is rich in Vitamin C and frost will actually improve its flavour. I really enjoy Vates, which is ruffled with a medium dark green leaf. By using a row cover, we were enjoying kale in our salads well into the fall.
RADISH
Radish is amazingly quick to germinate. I think they add the perfect crispy, peppery taste to a salad. If you plant the seeds early, it will be one of the first vegetables ready for harvest. Radishes also work well for Succession Planting. Radish varieties have evolved over the years and there are now several different sizes and colours. I enjoy the French Breakfast varieties.
PEAS
Homegrown peas, whether cooked or raw always taste amazing. Taller varieties do require some kind of support and will benefit from a fence or string for the vines. Dwarf varieties are ideal for smaller gardens and don’t require support. They do need lots of sun but will tolerate some shade in the summer. Smaller peas are tastier than larger ones, so be sure to harvest often. The edible garden pea dates back to 16th century England. I will admit not to have a lot of luck with peas. I may be getting them planted too late in the spring and with instant summer heat, they do not do well! I am determined to try again this year. My favourite are sugar snap peas and I would like to try one called Sugar Ann, that matures in 55 days and is a dwarf variety.
SPINACH
A favourite cool season vegetable to grow is the vitamin-rich spinach. Spinach can be eaten cooked or raw and is full of vitamins and minerals, especially iron and calcium. They mature quickly. As the plants grow, harvest the outer leaves often to encourage fresh leaf production, but pull the plants before they bolt. Once the flowering process begins, spinach quickly turns bitter, so don’t wait to harvest. Row covers are advisable to protect the plants from leaf miner. Many varieties have been developed to resist Downy Mildew.