Gardening in March

Posted on Friday, March 14, 2025 · Leave a Comment 

Whether March came in like the proverbial lion or lamb for you, March is the time when you need to pay more attention to your houseplants. Instead of watering every Sunday, you probably need to water most things twice a week – except for cacti and a few plants that thrive in dry soil. But rosemary? It’s so easy to kill now. The sun is hotter, roots are growing, and they need more water. Don’t keep the soil soggy, but poke your fingers into the soil more often and make sure it’s not Arizona arid. A dry rosemary is a dead rosemary.

 

Don’t leave stubs, they have to heal back to branch collar

Although March is the time farmers tend to prune their fruit trees, I am waiting a bit. We still have too much snow to easily move around carrying ladders. Pruning experts will tell you that you can prune fruit trees any month of the year, something I have found to be true. But let’s go over a few rules for pruning.

 

Use sharp tools. A good pair of hand pruners, some loppers and a pruning saw are all you need. I don’t like bow saws – they can’t get into tight places. Know where to cut. Don’t cut branches flush with the trunk or a big branch. Each branch has a “collar” that should be left. This is the bulge where it heals. But don’t leave long stubs when you remove a branch. They will not heal properly, and look awful. Remove dead branches first.

 

Never remove more than about a quarter of the leaf-producing branches. Leaves are the engine that drive growth and flower and fruit production. Remove water sprouts each year or two. These start as pencil thin shoots growing straight up, but will get big and clutter up the interior of the tree. Remove branches that are rubbing or crossing others, or are growing in towards the center of the tree. Remember: sunlight should be able to reach every leaf. Open up the interior so this is possible.

 

Homemade A frame plant stand for starting seedlings

March is also the time I start planting seeds indoors. Onion family seeds and peppers, hot and sweet, can be started now. Artichokes and cardoon I start early, but tomatoes I don’t start until around April 10. That will give them 8 weeks to be ready to go outside in mid-June.

 

Actually, it is much easier to order onions as bareroot plants sold in bunches of 50, each a few inches long and ready to start growing in the ground in May. Johnny’s Select Seeds and others sell them, and your local nursery may sell onions in 6-packs, each cell with 4 to 6 seedlings. The main advantage to starting onions or tomatoes by seed is that you get a much wider choice in what you grow.

 

If you want to start plants indoors, you will need some lights. Yes, some people try a sunny window, but they generally get lanky plants leaning toward the sunshine. Kits with LED or fluorescent lights are sold at garden centers and online. I built my own, a simple A-frame wooden structure that has two plywood shelves and supports 4-foot lights. It can accommodate up to 12 flats of seedlings if I put some on the floor.

 

Metal planting cells from Gardeners Supply

Next you need 6-packs of either plastic (like the ones you get when you buy veggies or annuals at the nursery) or re-usable metal or heavy duty plastic ones. In my efforts to reduce my use of single-use plastic, I have switched over to re-usable plant cells. Yes, they are more expensive, but they last forever. In any case, get bigger cells, not smaller ones. Your babies are going to grow in them for 8 weeks or more and need plenty of room for roots.

 

You can buy seed starting mix, but if you do a lot of plants (as I do), it can get expensive. So you can mix the potting mix with good quality compost if you have it, or you can buy it. Seed starting mixes don’t have much nutrition in them, so adding compost helps. Or later, you can water with a dilute solution of liquid fertilizer, something like Neptune’s Harvest Liquid Fish and Seaweed Fertilizer.

 

You may wish to buy electric heat mats designed to provide consistent low-level warmth. This signals the seeds that spring is here, and gets them to sprout sooner and with better germination rates. Again, expensive, but they last forever.

 

Lastly, you can’t let your seeds/seedlings dry out. One way to prevent that is to buy clear plastic covers that fit over a flat of seedlings. Oh, and don’t forget to buy trays to hold your 6-packs. This keeps water from getting on to your table or floor.

 

Lastly, in March I am reading gardening books and magazines and planning out what I want to do in my flower gardens. I recently got a preview copy of a wonderful book by my friend Jill Nooney called “Bedrock: The Making of a Public Garden”. Jill and her husband Bob Munger have working on their property to develop beautiful spaces to try all sorts of plants. They bought the house in 1980 and have been working on them ever since. They turned over most of the land, gardens and Jill’s sculpture to a non-profit to own and manage last year, but they continue to live in the old farmhouse there and work in the gardens.

 

Why read this book? It is relevant to anyone who wants to develop great gardens. Jill is a plant collector who has tried just about anything that will grow in a Zone 4/5 garden, and the photos illustrate many of them. The color photos are numerous and beautiful. It is full of design ideas, too. And she has an engaging writing style. I loved the book.

 

Spring is just around the corner. Get busy now – it will help prevent the mud season blues!

 

Henry’s column appears here once a month. Reach him at henry.homeyer@comcast.net.

Filed under Article · Tagged with Bedrock Gardens, Jill Nooney, starting seeds

Starting Seedlings Indoors: How, When, Where?

Is it time to start seedlings yet? Yes, for a few things: artichokes, broccoli, Brussels sprouts, cabbage, onions and leeks, kale and peppers. Tomatoes I start in early- to mid-April, along with eggplants, lettuce, melons and squashes of all sorts. Root crops are generally started outdoors later on, but I have started beets indoors on occasion for an extra early crop.

If you want a lot of annual flowers, starting by seed can be a big saving. But, as with vegetables, you have to do it just right in order to get plants that resemble the ones you would buy at the garden center.

If I just want a 6-pack of nasturtiums, it is cheaper to buy them as plants than as seeds. A packet of seeds often costs $5 or so, though the FEDCO cooperative sell little packets for just $1.30. Those packets generally contain a gram of seeds, and the on-line catalog tells you how many seeds are in it- usually plenty (or more than enough) for a one-year supply.

Most seeds are good for 3 years. But onions, sweet corn, parsnips and spinach are only good for one year. Peas, beets and Swiss chard are good for one or two years. Flowers vary – experience will tell you, or the seed package will. If you have older seed, plant more seeds – not all will germinate, but some probably will.

Equipment for seed starting

To get good looking plants, you need lights. Yes, there are people who start plants on windowsills, but those plants quickly get tall and leggy as they reach for light. If you want to start some lettuce seedlings in late April on a window sill, sure, you can keep them there for a month before putting them outside. But tomatoes? Forget about it.

Buy 4-foot fluorescent lights and hang them 6 inches above your seed flats. As the plants grow, move the lights up to keep them at the right distance. Now there are LED lights made for the same 4-foot fixtures you may already have, and they are supposed to be more effective and less expensive to run. They are available on-line from Gardeners Supply Company. LED lights should last for 20-plus years. I use something called jack chain, which I get at the hardware store, to hang my lights as it is easy to adjust the length of the chain.

I use a biodynamic calendar called Stella Natura (www.stellanatura.com) to guide me when to plant seeds. It uses the sun, moon and stars to determine when optimal dates are for planting. It also gives “black-out” days to avoid. I’ve tested the black-out days, and never plant on them. Sunday, April 8 will be good for starting tomatoes this year, but the 11^th to 13th will be black-out days.

Seeds have a built-in heat-sensitive trigger that controls germination. It would be a bad idea for a seed to germinate in January, for example, even if there were no snow. Cold would kill the seedlings. Warm soil tells a seed that the sun is strong, has been for some weeks, and probably will continue to be strong and warm.

You can add bottom heat to your seed flats by buying electric heat mats. They are about the size of a flat, and add a low, gentle heat to warm the starting mix your seeds are planted in. They will speed up germination considerably.

Potting Soil

Don’t even think of starting seeds in garden soil. Although I sometimes make soil blocks from compost and peat moss with some added garden soil, usually I just buy Moo-Doo brand planting mix that I put in little plastic 6-packs. I always buy the 6-packs that have the biggest cells available. Some come with 72 compartments to the flat, some 48 and others 36 or 32. I like the 32’s – they have more room for roots.

Seeds are very sensitive to drying out, especially just after they have germinated. To minimize the chances of that, I use plastic covers that fit on the flats. These are clear, allowing light to pass through, but not moisture. Safely stored, these are good for many years. You can save and wash the 6-packs but they are cheaply made and often crack or break, so I don’t bother most times.

Read the seed packets when planting seeds. Lettuce seeds need light to germinate, so just a very fine layer of planting mix or fine vermiculite will do. A big seed like a squash needs half an inch or more of cover. Generally the bigger the seed, the deeper the hole. I use a pencil to make a divot for each seed.

Because the Queen of the Garden is the tomato, I plant 2 seeds in each cell. Usually both germinate. The hard part is then snipping off one of the two. It feels awful to kill a tomato, but growing both in a small cell will result in stunted growth and completion for nutrients. And if the seedlings get too big, I transplant some into small pots.

Moisten potting mix before planting

As plants grow, they quickly use up the minerals that came in the potting mix. I make a dilute solution of fish and seaweed fertilizer and use it to water my seedlings. That’s what nurseries do, although most use chemical fertilizers – sometimes pushing the plants to grow too fast. And since I am not going to use chemical fertilizers, I don’t want plants that expect them.

Starting seedlings is a sure cure for MSB (Mud Season Blues). I love watering and admiring my little tomatoes, and dreaming of them in sandwiches on thick slices of all-grain bread with rich mayonnaise. Sigh. That’s still a long way off.

You may reach Henry by e-mail at henry.homeyer@comcast.net. His website is www.Gardening-Guy.com. 

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