In this months post, I will guide you through the essential gardening tasks, provide top horticultural tips and expert advice so you will know what to do and how to do it to bring out the best in your lawn and garden during this busy gardening month of April.
April Showers Brings May flowers, as the saying goes. And I recite that when I'm slugging it out in the garden in the pouring rain, to remind myself it is indeed a good thing!
Rain aside, April is a beautiful month of new beginnings; of fresh green growth, cheerful spring flowering bulbs and colorful flowering shrubs. There is increased wildlife activity as birds fly about feeding their young and bumblebees appear with the early spring blooms of Flowering Currant and Winter Heather which provide them with early sources of nectar and pollen. Spring has truly arrived this month.
When the sun comes out it is lovely here on the West Coast and its rays highlight the gorgeous blooms of the abundant flowering ornamental cherry trees
that line Vancouver's city streets and brighten our parklands.
Other flowering highlights include early spring bulbs of Daffodils, Hyacinths, early Tulips and Snakes Head Fritillary, flowering shrubs of Forsythia, Star Magnolia, Viburnums, Flowering Quince and of course Rhododendrons and Azaleas which are so abundant in gardens here on the west coast.
The lawn is greening up nicely and begins to grow vigorously this month and requires much attention and regular maintenance. I find myself particularly busy with lawn care and lawn improvement projects on client properties this month. Lawns require regular mowing now and this is the time to repair sparse or thin turf with aeration, dethatching (if needed), topdressing and overseeding. Lawn care is this months spotlight feature which I discuss in great detail as well as give my top tips for a creating a thriving, vibrant and healthy lawn.
Now that spring is truly here, there is much to be done this month; beds to be prepared, trees and shrubs to be planted, seeds to be sown and lawns to be mowed and improved upon. I discuss these important jobs below so please do read on.
Jobs for April Checklist:
Finish pruning Roses by early April and mulch surface with compost or finished manure. See my Rose pruning article for detailed instructions on how to prune different types of Roses and when.
Shear winter flowering Heather once it has finished flowering
Trim over Lavender to remove spent flower stalks and clip over up any winter damaged foliage while refraining from cutting too hard into woody stems
Lavender does not create new growth easily from old stems so don't cut back into the woody stems
Hedge trim evergreen hedges this month
Plant Dahlia tubers outside and other summer flowering tubers, corms and bulbs
Prune Mophead and Lacecap Hydrangeas
Macrophylla (Mophead & Lacecap incl. Serrata): Light pruning required to deadhead and remove dead, damaged and oldest unproductive canes
These flower on older wood rather than the new seasons growth
Remove dead stems, badly rubbing stems and one or 2 of the oldest unproductive stems (thick and grey colored) to reduce congestion and improve light and airflow
Prune frost damage stems back to above a healthy set of buds. Deadhead to above the next healthy set of buds
After pruning mulch with compost or finished manure
Set up plant supports around herbacious perennials that need support such as Paeonies, Delphinium etc before they become too big and flop over
The correct time to support any plant is before it needs to be done to prevent damaging growth while trying to fit it into support rings etc.
Plant evergreen trees and shrubs and mulch soil with 2 inch layer of compost, composted bark mulch or bark mulch
Mulch around shrubs, trees and hedges with appropriate mulching medium- See spotlight feature of March blog for mulching information.
Mulch any exposed bare soil in garden beds to suppress weed growth. Weed beds prior to mulching
Keep on top of hand weeding garden beds and lawns to prevent spread of weeds when they go to seed
Edge lawn borders with line trimmer or half moon shaped edging shovel
Remove finished flowering heads of Daffodils but leave the foliage until its yellow and cut back when it has died back as it continues to feed the bulb for improved flowering next spring
Continue to lift, divide and move perennials
This month continues to be a great time to plant hardy or woody perennials
Complete cutting back of Ferns early in April so not to damage newly emerging fiddleheads
Turn the compost pile and aerate it through flipping or opening up pile with a garden fork
Harden off tender plants by gradually introducing them outside so that they can gradually acclimatize before being planted out into a border or pot
Put them outside in a sunny but sheltered spot let them get used to the changes in temperature and exposure to wind and rain that they have not had to face over the past few months for at least a week and preferably two before moving them to their final position after the risk of any frost has passed
For new seedlings ready to be planted out, gradually introduce them by bringing them outside in a sheltered spot for a few hours a day and bringing them back in. Do this for 5 days or so and each day increase the number of daylight hours you have them outside
Vegetables and Herbs:
Sow tomato, sweet peppers, cucumber and globe artichoke indoors
Hardy herbs and veggies to be sown or planted outside include lettuce, carrots, chervil, peas, spinach, radishes, broad beans, cabbages, beetroots, potatoes, onion sets, parsnips, Leeks, Strawberry, artichokes and asparagus.
Tomatoes-Sow tomato seeds indoors in plug cells or small 3 inch plastic or fiber pots. Keep moist and warm on heated mat on windowsill or greenhouse until they germinate
Keeping out of direct sunlight on sunny days by moving out of direct sun or having a shade cloth or thin curtains that still allow some light through
Plant chitted potatoes outdoors in garden beds or in potato bags. I have limited garden space so I use potato grow bags and plant approx 2-3 potatoes in each bag. I used compost as the planting medium.
For an excellent guide to growing potatoes in a bag check out Westcoast seeds https://cdn.shopify.com/s/files/1/0011/2341/8172/files/How-to-Grow-Potatoes-in-a-Grow-Bag.jpg
Lettuce-This is the ideal time to sow lettuce seed direct into the soil outside as the soil is now warm and they will grow fast.
Lettuce needs cool temperatures to germinate, and may become dormant if the soil is above 20 degrees. They like a rich soil with good drainage.
Most lettuce take about 6 to 8 weeks to grow sufficiently large to eat and will be good for another month or so if kept watered and cool. Lettuces grow best in mild, moist conditions so a hot, dry summer is as big a problem as a cold winter. However many lettuces are happy in some shade as this will keep them cooler.
A few seeds sown thinly will provide healthier, leafier lettuces than a mass of thick seedlings
As they appear, weed and thin carefully to a final spacing of at least 4". Concentrate on growing healthy, strong plants rather then having overcrowded weaker growth.
Rocket or Arugula can be direct sown outdoors now in the veggie garden or in pots. Be sure to ruthlessly thin them as widely spaced plants are much healthier, give a bigger harvest and last longer.
Rocket does not like hot weather and needs rich soil with plenty of water to be at its best. It is best sown in Spring and Autumn.
I like to sow seeds of Calendula and Nasturtiums along the front border edges of my raised veg bed as companions plants to my herbs and vegetables.
They attract pollinators and repel some unwanted insects and pests. Their flowers are also edible and great in salads and compound butters.
Harden off tender new seedlings and plants when it comes time to transplanting outdoors by slowly introducing them outside for a few hours a day, in a sheltered position, before planting permanently outside with full sun exposure
Lindsay's Top Tips:
Best lawn care practices-
Mowing-Mow weekly and take off no more then 1/3rd of blade height at each mowing. Set the blades at 2 1/2 to 3 inches. Make sure the blades are reasonably sharp. Regular weekly mowing allows you to keep pace with the cutting so you aren't taking off too much new growth at once. Mowing too high or too low will weaken lawns. Proper regular mowing reduces stress on the grass and results in a denser turf. Resist mowing too short as this will encourage good root growth and as a result the grass will be a lot healthier and better able to resist summer drought.
The exception to this are types of grass species used on golf courses such as genetically designed low growing Perennial Rye grasses and also Bent Grass which require frequent low mowing to as low as 1/2" twice a week and frequent dethatching on a biannual basis.
These are less common species of grass used for residential lawns but I mention them because I have a client who has a Bent Grass lawn as he wanted a "golf course" style lawn and it is managed differently to traditional residential lawns so it is good to know what species of grass you are dealing with.
Mulch mow if grass is not too long or too wet as it provides nitrogen and other nutrients to the lawn. If there is heavy weed pressure or weeds are going to seed, bag the clippings as mulching will spread the weeds further.
Aerating-Aerate as soon as March if you're not overseeding the lawn but rather encouraging the existing grass to performance better. If overseeding to thicken or repair lawns, wait until daytime temperatures are above 10 degrees (and between 10-25 degrees celsius) for optimum seed germination and this is usually in April and May here on the West Coast of the Pacific Northwest.
For larger lawns I rent a mechanical aerator and have it delivered as it weights in excess of 250lbs! For smaller lawns I use a manual foot press aerator.
Tip-Where possible hire a company to do the mechanical aerating for you as it is a beastly machine to operate. I can attest to that.
Topdressing-For topdressing a typical residential lawn surface after aerating or dethatching and just prior to over-seeding, you want a double-screened lawn topdressing which consists of approx 65/35 golf sand/compost. 70/30 or 60/40 is fine as long as it's double screened and contains minimal or no bark mulch or wood chips. The sand improves drainage while the compost provides a good nutrient base for seeds to germinate and establish and also feeds the existing grass. Straight golf course sand can be used where the lawn is being aerated but not over-seeded. Bent Grass lawns and golf course turf are best topdressed with straight golf sand after being heavily dethatched and aerated once or twice a year.
Fertilizing-Fertilize lawn later in Spring and not as soon as this month. Wait until May when grass tips are actively growing. In winter and early spring, grass is putting its energy into root establishment/growth which is important for its ability to cope with drought conditions. The more established and deeper the roots, the better it can handle drought and require less watering. We do not want to encourage the lawn to prematurely switch from this process to putting energy into early tip growth at the expense of root growth.
I like to use an organic slow release spring lawn fertilizer in the nutrient range of 16-2-3 or 14-4-8.
Moss in lawns and what to do about it-Excessive Moss growth is attributed to the soil being very acidic and compacted, poor drainage or the area is too shaded and receives inadequate sunlight. Often the reason for moss in a lawn is a combination of all these factors. Grass loves the opposite conditions: slightly alkaline soil, a minimum of six hours of sunshine a day, and well-drained soil. If you want to grow grass instead of moss you have to change the conditions: Spread Dolomite lime to raise the level of alkalinity; aerate and brush in 50/50 topdressing to improve drainage and reduce compaction; and raise the light levels by removing a few branches from trees or shrubs that are shading the area. There are also spring fertilizer products with moss control which is often in the form of added Iron.
As the weather improves and it becomes warmer and drier, moss often dies back naturally and can then be raked up. Follow up with topdressing and overseeding to fill in the bare patches left by the removed moss.
Simplified improvement project for small lawns-If you have a small lawn space, you can do a pared down version of the lawn improvement project by giving the lawn a good scratch with a wire rake to get at all the overwintering thatch and moss, and let light and water get to the soil and to the roots of the grass. Put the debris on the compost and then mow to even out the lawn. Then consider manually aerating with a foot press aerator, lightly topdressing the surface and overseeding with the appropriate grass seed mix for your turf's growing conditions.
Repairing Chafer grub damaged lawns-Repairing a chafer damaged lawn involves raking up the damaged turf and either retaining salvageable existing turf and overseeding with the standard Perennial Rye Overseed or starting over with a Tall Fescue/Micro-Clover mix. Follow the lawn improvement/repair steps below but consider overseeding with Tall Fescue and Micro-Clover instead of the susceptible perennial rye. It is more resistant to grub infestation as the adult beetles look to lay their eggs in patches of bare soil that can be found in a lower growing less dense turf. The grubs can gain easier access to feeding off the root system of the grass where the turf is thinner and soil is exposed. The tall fescue provides a denser cover and the fescue can be mowed at a higher height which makes accessing the soil level harder for the beetles and laying of grub eggs and the clover is not a food source for the grubs at all so is fully resistant. I don't often choose to use straight clover however, as it dies back in winter until it re-emerges in spring leaving unsightly bare soil all winter which weeds can take advantage of prior to the re-establishment of the clover species. I will discuss available methods to prevent chafer grub infestation in the June blog as this is closer to when biological management products can be used. Good lawn maintenance practices to promote a dense healthy turf are vital in chafer prevention in addition to the biological management practices available.
Spotlight on Spring lawn improvement for a thriving, healthy lawn:
When to do: Aerate as soon as March if not overseeding but if overseeding wait until daytime temperatures are above 12 degrees for optimum seed
germination and this is usually in April and May here on the West Coast of the Pacific Northwest.
Why to take these steps to improve lawns: Aeration reduces compaction, improves drainage and allows oxygen, water and amendments to penetrate the root zone while dethatching removes excessive thatch build-up that shades out new growth and can prevent fertilizer and amendments from reaching the soil level where they deliver benefits. Topdressing with a 50/50 sand and compost blend improves drainage and adds organic matter below the root system (as it is worked into the aeration holes) which is important for healthy growth and also provides a medium for grass seed to germinate in.
Tools/equipment for the job: Lawn mower, foot aerator or rented mechanical aerator, rented power-rake or dethatching machine (if doing dethatching step); for spreading topdressing-wheelbarrow, shovel, hard rake, 18" or larger spring rake; broadcast spreader such as Scotts brand spreader for broadcasting dolopril, seed starter fertilizer and grass seed and a hose with long reach rotating sprinkler head attachment (if no irrigation system).
The steps I take for my lawn renovations and improvements are as follows:
Mow the lawn at a lower setting then normal, setting the blade height to approx 2" and bag the clippings.
If there is a build-up of thatch more then 1/2 thick, then use a rented mechanical power-rake or dethatcher to dethatch the lawn. This is laborious as it requires doing 2 passes or so in alternative directions and raking up all the dethatched material off the surface between passes. Remove and compost the thatch collected or take to greenwaste station. I sometimes mow again to collect remaining thatch or even out remaining grass that is sticking up and looking scraggly from being power-raked. The power-raking or dethatching removes quite a bit of grass in addition to thatch and scarifies the surface so you will want to primarily focus on ensuring new seed establishes to fill the lawn back in, more so then relying on remaining existing grass to do the job.
After dethatching and collecting the thatch, you then move to aerating the lawn. If no dethatching is required then skip that step and go straight from mowing to aerating. Aerate with a rented mechanical aerator on larger lawns or using a manual foot aerator on smaller lawns. Suppliers will deliver aerators and pick up again using a truck with a hydrolic lift and this is definately the way to go as the machines weight in excess of 250lbs! I have tried to pick them up in my pickup truck using ramps and it has been a nightmare so get them delivered or even better, hire a company to do this for you!
You can rake up the plugs to tidy up the surface but it feeds back into the soil to leave them on.
If not already done last month, apply Dolopril Lime to the aerated/dethatched surface. This is a good time to do so as it allows the lime to reach root system directly.
Then I spread a seed starter fertilizer prior to topdressing if relying predominantly on new seed to establish rather then existing lawn to return which may be the case after dethatching or where lawn has large bare sections needing repair from chafer grub digging damage or areas where excessive moss was removed.
Next spread lawn topdressing on the surface which is approx 65/35 or 60/40 golf sand/compost that has been well screened and contains minimal bark mulch or wood chip. The sand is good for improving drainage and the compost provides nutrients to the grass. The blend of the 2 provides a good medium for grass seed germination also.
I use a wheelbarrow to deliver piles to the lawn, then use the flat side of a hard rake to spread it and a metal rake to brush it in and spread it further.
I aim to topdress the surface 1/4" to 1/2 thick. You dont want to go too thick as existing grass can rot below the topdressing and struggle to grow through it. You want to encourage existing grass to return rather then bury it entirely. If there isn't much existing grass being encouraged to come back and its mostly a matter of new seed germinating, then you can go thicker on the topdressing.
Next use a spreader and apply the appropriate grass seed for your region and growing conditions. The most suitable seed for coastal lawns is Perennial Rye grass. This seed creates a fine lawn that is incredibly resilient and once established, is also quite drought tolerant Grass seed suppliers sell perennial rye blends that are suitable for overseeding existing residential turfs. There are also rapid Ryegrass overseeding mixes that establish quickly where outcompeting weed pressure may be high. For shady lawns there are shade specific grass seed blends of fine-textured lawn seed created for shady, damp or acidic soil conditions. These contain a blend of Perennial Ryegrass, Creeping Red Fescue, Chewings Fescue and Creeping Red Fescue.
Where chafer grub damage has occurred, I have repaired and overseeded lawns using a blend of tall fescue and micro-clover. See the images below for an idea of this type of lawn. It is more resistant to grub infestation as the adult beetles look to lay their eggs in bare soil so the grubs can gain access to feeding off the root system of the grass. The tall fescue and micro-clover provide a denser cover and the fescue can be mowed at a higher height which again makes accessing the soil level harder for the beetles. I don't often opt to use straight clover as it dies back in winter and re-emerges in spring leaving unsightly bare soil all winter which weeds can also take advantage of prior to the re-establishment of the clover species.
If you have a larger lawn area rent a drum roller to press the seed into the soil as you need good seed to soil contact for germination.
Then be sure to run your irrigation or set up a rotating sprinkler with good coverage to water the newly seeded lawn. I run clients irrigation on for 30-45 mins per coverage zone depending upon the irrigation system's water pressure and volume of water emitted. Some are weaker then others but the idea is to moisten the soil well. The key to germination is to continue to water daily on non-rain days or where there is only light rain at least once a day and on drier warmer days watering twice a day in the morning and later afternoon to unsure the surface does not dry out. Simplified project for small lawns-If you have a small lawn space, you can do a pared down version of the lawn improvement project by giving the lawn a good scratch with a wire rake to get at all the overwintering thatch and moss, and let light and water get to the soil and to the roots of the grass. Put the debris on the compost and then mow to even out the lawn. Then consider manually aerating with a foot press aerator, lightly topdressing the surface and overseeding with the appropriate grass seed mix for your turf's growing conditions.
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